High-power cordless, hand-held power tool including a brushless direct current motor

ABSTRACT

A cordless, hand-held power tool, such as a hammer drill/driver, an impact driver, an impact wrench, etc., that includes a brushless direct current (“BLDC”) motor. Each of the hand-held power tool includes a removable and rechargeable battery pack, electronics, and a BLDC motor that have been designed and balanced to produce high-performance-capable (e.g., high-power, high-current, high-torque) hand-held power tool. The hand-held power tool is capable of delivering high instantaneous (i.e., short duration) current to the BLDC motor for short-duration high power operation and high continuous (i.e., long duration) current to the BLDC motor for long duration high power operation. Additionally, the short and long duration power is capable of being provided in a smaller (in size) and lighter (in weight) power tool.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.17/499,065, filed Oct. 12, 2021, now U.S. Pat. No. 11,370,099, which isa continuation of U.S. patent application Ser. No. 17/085,120, filedOct. 30, 2020, now U.S. Pat. No. 11,141,851, which is a continuation ofU.S. patent application Ser. No. 13/838,126, filed Mar. 15, 2013, nowU.S. Pat. No. 10,821,591, which claims the benefit of U.S. ProvisionalPatent Application No. 61/725,961, filed Nov. 13, 2012, the entirecontent of each of which is hereby incorporated by reference.

BACKGROUND

The present invention relates to a hand-held power tool that includes amotor and is powered by a battery pack.

SUMMARY

Power tools can generally be grouped into two categories: cordless powertools and corded power tools. Conventionally, regardless of whether apower tool was a cordless power tool or a corded power tool, the powertool included a brushed-type motor (i.e., motor brushes provide anelectrical connection to the rotor of the motor).

A different type of motor, brushless-type motors, have not been widelyused in power tools as a result of their prohibitively high cost, designconsiderations necessary for motor control electronics, and difficultiesassociated with designing a system that is capable of delivering theperformance required of a variety of different power tools.

For example, practical considerations for designing a power tool includethe application that the power tool will be used for, the performancerequired or desired of the power tool, the manner in which the powertool is being used, the size of the power tool, the weight of the powertool, the cost of the power tool, etc. Balancing these and otherconsiderations in an optimal manner when designing a power tool dictatethe ultimate design of the power tool. However, in some instances,selecting one of the above design considerations often limits theavailable options for one or more of the remaining design considerations(e.g., small size often reduces the power that can be produced, reducingcost often reduces performance characteristics, increasing the weightlimits the applications for which the power tool can be used, etc.).

These limitations are magnified when attempting to manipulate thesevarious design considerations in a power tool that includes abrushless-type motor, as a result of the difficulties associated withharmonizing motor control electronics, power source requirements, andmotor capabilities to achieve desired performance and operationalcharacteristics. This is particularly true of the subset of cordlesspower tools referred to in the art as hand-held power tools (i.e., powertools that are capable of being held in a user's hand and the size andweight of the power tool can be supported by the user).

Such hand-held power tools are real world products. Over the years, manyof the basic design considerations related to hand-held power tools havebeen designed and refined. The results of this design evolution areconsistent and established form factors, as well as establishedstandards of performance for a variety of different hand-held powertools (e.g., hammer-drills, drill-drivers, impact drivers, impactwrenches, etc.) and applications of those hand-held power tools.

For example, the form factors for hand-held power tools, whether poweredby a battery pack or by alternating current (“AC”) power, must have asize, shape, and weight such that they can be hand-held and supported bya user, which imposes practical limitations on, for example, the sizeand characteristics of the hand-held power tool's motor (e.g., number ofmotor windings), the size of the gear reduction within the hand-heldpower tool, the type and size of accessory (e.g., drill bits, sawblades, etc.) connected to the power tool, the torque required to drivethat accessory (e.g., larger saw blades generally require greater torqueresulting from a deeper cut; denser materials require more torque tocut, etc.), etc. Accordingly, as a result of these considerations, manycharacteristics of hand-held power tools have either already beendecided (e.g., based on the requirements of the type of tool and theapplication of the tool) or have a relatively limited range of potentialvariation (e.g., size, weight, etc.). As a result, the performancecapabilities of such hand-held power tools have also had a limited rangeof potential variation.

The three primary electrical components in a cordless hand-held powertool that affect performance are the battery, which provides power tothe hand-held power tool, the motor, which drives the output device ofthe hand-held power tool, and the electronics, which monitor and controlthe operation of the hand-held power tool. These components can bemodified and/or optimized individually or in concert in order to improvethe performance of the hand-held power tool.

For example, when designing a motor, a desired outcome may be to producea motor that is able to deliver the highest output power (i.e., in Watts[“W”]) while maintaining the durability of the hand-held power tool andthe motor. In designing such a motor, the motor must also fit within thesize and cost constraints for a particular hand-held power tool, asdescribed above. Durability in the context of hand-held power toolsgenerally refers to electrical durability (i.e., the ability of thehand-held power tool to produce both short-term, high or peak levels ofcurrent and long-term, sustained high levels of current without causinga fault condition [e.g., overheating]). Similar to motor design, it maybe desirable for the battery pack that provides power to the hand-heldpower tool to deliver the highest possible short-term or short-durationlevel of current, as well as the highest possible long-term or sustainedlevel of current.

A variety of techniques can be implemented to improve the performance ofa hand-held power tool and achieve these desired characteristics. Forexample, by reducing the resistance (e.g., internal resistance) for oneor more of the motor, battery pack, and electronics within the hand-heldpower tool, the performance of the hand-held power tool can be improved.Another technique includes improving the ability of the hand-held powertool to dissipate the heat that is generated during operation by thebattery pack, the motor, switches, etc. Whether one or all of theimprovements described herein are implemented, the performance of ahand-held power tool is improved by balancing the design andcapabilities of the hand-held power tool's motor, the design andcapabilities of the battery pack providing power for the motor, and thedesign and capabilities of the electronics associated with the hand-heldpower tool and the battery pack for delivering power from the batterypack to the motor. Balancing these aspects of a hand-held powertool/battery pack combination allows for increased performance (e.g.,maximum sustained output power, maximum short-duration output power,etc.), without the hand-held power tool or the battery pack failing(e.g., experiencing a thermal failure).

Accordingly, the invention described herein relates to a cordless,hand-held power tool with improved performance. The hand-held power toolincludes a brushless direct current (“BLDC”) motor, electronics forcontrolling and monitoring the operation of the hand-held power tool,and a battery pack that is removably coupled to the hand-held power toolto provide power to the hand-held power tool.

In one embodiment, the invention provides a hand-held power toolconnectable to a removable and rechargeable battery pack. The power toolincludes a housing, a trigger switch, a plurality of power terminals, aplurality of power switching elements, a motor controller, a BLDC motor,and an output shaft. The trigger switch is configured to selectivelyoutput a trigger signal to the motor controller. The power terminals arepositioned within the housing of the hand-held power tool and areconfigured to receive electric current from the battery pack. The powerswitching elements are positioned within the housing of the hand-heldpower tool and are electrically connected to the power terminals. Themotor controller is electrically connected to the power switchingelements and to the trigger switch to receive the trigger signal. Themotor controller is configured to selectively enable and disable thepower switching elements based on the trigger signal. The BLDC motor iselectrically connected to the power switching elements such that theselective enabling and disabling of the power switching elementsselectively provides power to the BLDC motor. The hand-held power toolhaving an average sustained (e.g., long-run) power output of at leastapproximately 300 Watts. The output shaft coupled to and rotationallydriven by the BLDC motor to provide an output force.

In another embodiment, the invention provides a hand-held power toolincluding a housing, a trigger switch, a first battery terminal, asecond battery terminal, a brushless direct-current (“BLDC”) motor, aswitching array, a controller, and an output shaft. The housing includesa body and a handle portion. The trigger switch is configured togenerate a trigger signal. The first battery terminal and the secondbattery terminal are configured to electrically connect to a batterypack. The battery pack includes a plurality of lithium-based batterycells, and the battery pack is removably coupled to the hand-held powertool. The switching array includes a plurality of switches electricallyconnected between the BLDC motor and the first battery terminal and thesecond battery terminal. The controller is configured to receive thetrigger signal from the trigger switch, and generate a control signalbased on the trigger signal to selectively enable and disable each ofthe plurality of switches in the switching array to drive the BLDC motorwith power provided from the battery pack. The output shaft is coupledto the BLDC motor to provide an output of the hand-held power tool, andthe hand-held power tool is operable to produce an average long-durationpower output of at least 300 Watts (“W”) and a maximum short-durationpower output of at least 400 W.

In another embodiment, the invention provides a hand-held power toolincluding a first battery terminal, a second battery terminal, abrushless direct-current (“BLDC”) motor, a switching array, acontroller, and an output shaft. The first battery terminal and thesecond battery terminal are configured to electrically connect to abattery pack. The battery pack includes a plurality of lithium-basedbattery cells, and the battery pack is removably coupled to thehand-held power tool. The switching array includes a plurality ofswitches electrically connected between the BLDC motor and the firstbattery terminal and the second battery terminal. The controller isconfigured to generate a control signal to selectively enable anddisable each of the plurality of switches in the switching array todrive the BLDC motor with power provided from the battery pack. Theoutput shaft is coupled to the BLDC motor to provide an output of thehand-held power tool, and the hand-held power tool is operable toproduce a maximum short-duration power output of at least 450 W.

In another embodiment, the invention provides a hand-held power toolincluding a first battery terminal, a second battery terminal, abrushless direct-current (“BLDC”) motor, a switching array, acontroller, and an output shaft. The first battery terminal and thesecond battery terminal are configured to electrically connect to abattery pack. The battery pack includes a plurality of lithium-basedbattery cells, and the battery pack is removably coupled to thehand-held power tool. The switching array includes a plurality ofswitches electrically connected between the BLDC motor and the firstbattery terminal and the second battery terminal. The controller isconfigured to generate a control signal to selectively enable anddisable each of the plurality of switches in the switching array todrive the BLDC motor with power provided from the battery pack. Theoutput shaft is coupled to the BLDC motor to provide an output of thehand-held power tool, and the hand-held power tool is operable toproduce a maximum short-duration power output of at least 700 W.

In another embodiment, the invention provides a hand-held power toolconnectable to a removable and rechargeable battery pack. The power toolincludes a housing, a trigger switch, a plurality of power terminals, aplurality of power switching elements, a motor controller, a BLDC motor,and an output shaft. The trigger switch is configured to selectivelyoutput a trigger signal to the motor controller. The power terminals arepositioned within the housing of the hand-held power tool and areconfigured to receive electric current from the battery pack. The powerswitching elements are positioned within the housing of the hand-heldpower tool and are electrically connected to the power terminals. Themotor controller is electrically connected to the power switchingelements and to the trigger switch to receive the trigger signal. Themotor controller is configured to selectively enable and disable thepower switching elements based on the trigger signal. The BLDC motor iselectrically connected to the power switching elements such that theselective enabling and disabling of the power switching elementsselectively provides power to the BLDC motor. The hand-held power toolhaving a peak (e.g., short-run) power output of at least approximately400 Watts. The output shaft coupled to and rotationally driven by theBLDC motor to provide an output force.

In another embodiment, the invention provides a hand-held power toolconnectable to a removable and rechargeable battery pack. The power toolincludes a housing, a trigger switch, a plurality of power terminals, aplurality of power switching elements, a motor controller, a BLDC motor,and an output shaft. The trigger switch is configured to selectivelyoutput a trigger signal to the motor controller. The power terminals arepositioned within the housing of the hand-held power tool and areconfigured to receive electric current from a power source. The powerswitching elements are positioned within the housing of the hand-heldpower tool and are electrically connected to the power terminals. Themotor controller is electrically connected to the power switchingelements and to the trigger switch to receive the trigger signal. Themotor controller is configured to selectively enable and disable thepower switching elements based on the trigger signal. The BLDC motor iselectrically connected to the power switching elements such that theselective enabling and disabling of the power switching elementsselectively provides power to the BLDC motor. The BLDC motor has amaximum sustained power output of at least 1.0 watts per second whendischarging a battery pack throughout a discharge cycle (i.e., until thebattery pack reaches a low-voltage cutoff). The output shaft is coupledto and rotationally driven by the BLDC motor to provide an output force.

In another embodiment, the invention provides a hand-held power toolconnectable to a removable and rechargeable battery pack. The power toolincludes a housing, a trigger switch, a plurality of power terminals, aplurality of power switching elements, a motor controller, a BLDC motor,and an output shaft. The trigger switch is configured to selectivelyoutput a trigger signal to the motor controller. The power terminals arepositioned within the housing of the hand-held power tool and areconfigured to receive electric current from a power source. The powerswitching elements are positioned within the housing of the hand-heldpower tool and are electrically connected to the power terminals. Themotor controller is electrically connected to the power switchingelements and to the trigger switch to receive the trigger signal. Themotor controller is configured to selectively enable and disable thepower switching elements based on the trigger signal. The BLDC motor iselectrically connected to the power switching elements such that theselective enabling and disabling of the power switching elementsselectively provides power to the BLDC motor. The hand-held power toolhaving an average sustained (e.g., long-run) torque output of at leastapproximately 95 inch-pounds. The output shaft coupled to androtationally driven by the BLDC motor to provide an output force.

Other aspects of the invention will become apparent by consideration ofthe detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-7 illustrate a hand-held power tool according to an embodimentof the invention.

FIGS. 8-12 illustrate a hand-held power tool according to anotherembodiment of the invention.

FIGS. 13-17 illustrate a hand-held power tool according to anotherembodiment of the invention.

FIGS. 18-22 illustrate a hand-held power tool according to anotherembodiment of the invention.

FIGS. 23-35 illustrate a hand-held power tool motor according toembodiments of the invention.

FIGS. 36-40 illustrate a battery pack for a hand-held power toolaccording to an embodiment of the invention.

FIGS. 41-43 illustrate a battery pack for a hand-held power toolaccording to another embodiment of the invention.

FIGS. 44-47 illustrate electronic circuitry for a hand-held power tooland a battery pack according to embodiments of the invention.

FIGS. 48-50 illustrate printed circuit boards for hand-held power toolsaccording to embodiments of the invention.

DETAILED DESCRIPTION

Before any embodiments of the invention are explained in detail, it isto be understood that the invention is not limited in its application tothe details of construction and the arrangement of components set forthin the following description or illustrated in the following drawings.The invention is capable of other embodiments and of being practiced orof being carried out in various ways.

Embodiments of the invention described herein related to a compactcordless, hand-held power tool that includes a brushless direct current(“BLDC”) motor. The hand-held power tool includes, for example, ahousing, a motor, control electronics, a battery pack connectable to andsupportable by the housing, one or more terminals for electricallyconnecting the battery pack to the control electronics, a trigger, andan output device or mechanism to be driven by the motor. The specificcomponents of the hand-held power tool will be described in greaterdetail below with respect to specific, exemplary hand-held power tools.The hand-held power tool can be, for example, a hammer drill/driver, adrill/driver, an impact driver, and impact wrench, etc.

Each of the exemplary hand-held power tools described herein includes abattery pack, electronics, and a BLDC motor that have been designed toproduce a high-performance-capable (e.g., high-power, high-current,high-torque) hand-held power tool. For example, the hand-held power toolis capable of delivering higher instantaneous (i.e., short duration)current to the BLDC motor for short-duration high power operation, andhigher continuous (i.e., long duration) current to the BLDC motor forlong-duration high power operation than any cordless, hand-held powertool before it. Additionally, the short and long duration power iscapable of being provided in a smaller (in size) and lighter (in weight)package than any hand-held power tool before it. The hand-held powertools described herein strike a balance between the short-durationdelivery of current and power, as well as the long-duration (i.e.,continuous) delivery of current and power in order to provide ahigh-performance, high-power brushless hand-held power tool that iscapable of being used in a variety of different applications and under avariety of different conditions to meet the needs of a variety ofdifferent users.

The hand-held power tools match and balance the capabilities of the BLDCmotor, the battery pack, and the electronics. These three components ofthe hand-held power tool represent the three most significant potential“weak links” for the hand-held power tool. For example, if too muchcurrent is drawn from the battery pack by the motor and the power toolelectronics, the battery pack, or the battery cells within the batterypack, can overheat, reach an over-current condition, etc. In such aninstance, the battery pack shuts down in order to prevent a catastrophicfailure (i.e., a lithium-based battery cell or battery pack isdestroyed, suffers irreversible damage, or is rendered inoperable).

Alternatively, if the battery pack provides too much current or themotor draws too much current, the electronics within the hand-held powertool can also fail. For example, electrical and electronic componentssuch as field-effect transistors (“FETs”), wires, integrated circuits(“ICs”), etc., have current and temperature ratings which, if exceeded,will cause the electrical and electronic components to fail.

In order to maximize the performance capabilities of a hand-held powertool, the limits of these components should be considered and balanced.Otherwise, if a user attempts to operate the hand-held power tool at acurrent or power level that exceeds the operational capabilities of thehand-held power tool, the hand-held power tool, in one or more places,may fail. Accordingly, by balancing the capabilities of the hand-heldpower tool's motor (e.g., the current and power that can be provided tothe motor) with the capabilities of the battery pack providing power forthe motor (i.e., the maximum current and power than can be provided tothe hand-held power tool) and the capabilities of the electronicsassociated with the hand-held power tool and the battery pack fordelivering power from the battery pack to the motor (e.g., ensuring thatthe electronics do not fail under high-power or high-performanceoperating conditions), the performance capabilities of the hand-heldpower tool are increased or maximized without the hand-held power toolof the battery pack failing (e.g., experiencing a thermal failure oranother fault condition).

The cordless, hand-held power tool illustrated in FIGS. 1-7 is a hammerdrill/driver (“hammer drill”) 100. The hammer drill 100 includes anupper main body 105, a handle portion 110, a battery pack receivingportion 115, a mode selection portion 120 (e.g., for selecting among adrilling mode, a driving mode, a hammer mode, etc.), a torque adjustmentdial or ring 125, an output drive device or mechanism (e.g., a chuck)130, a forward/reverse selection button 135, a trigger 140, and airvents 145. The hammer drill 100 also includes a worklight 150, and thebattery pack receiving portion 115 receives a battery pack (see FIGS.36-43 ) and includes a terminal assembly 160 including a plurality ofterminals. The number of terminals present in the receiving portion 115can vary based on the type of hand-held power tool. However, as anillustrative example, the receiving portion and the terminal assemblycan include a battery positive (“B+”) terminal, a battery negative(“B−”) terminal, a sense or communication terminal, an identificationterminal, etc. The outer portions or housing of the hammer drill 100(e.g., the main body 105 and the handle portion 110) are composed of adurable and light-weight plastic material. The drive mechanism(described below) is composed of a metal (e.g., steel) as is known inthe art.

The battery positive and battery negative terminals are operable toelectrically connect the battery pack to the hand-held power tool andprovide operational power (i.e., voltage and current) for the hand-heldpower tool from the battery pack to the hand-held power tool. The sensoror communication terminal is operable to provide communication orsensing for the hand-held power tool of the battery pack. For example,the communication can include serial communication or a serialcommunication link, the transmission or conveyance of information fromone of the battery pack or the hand-held power tool to the other of thebattery pack or hand-held power tool related to a condition orcharacteristic of the battery pack or hand-held power tool (e.g., one ormore battery cell voltages, one or more battery pack voltages, one ormore battery cell temperatures, one or more battery pack temperatures,etc.).

The identification terminal can be used by the battery pack or thehand-held power tool to identify the other of the battery pack or thehand-held power tool. For example, the hand-held power tool can identifythe battery pack as a high capacity battery pack or a normal capacitybattery pack, as a lithium-based battery or a nickel-based battery, as abattery pack having a particular voltage (described below), a higherresistance battery pack, a lower resistance battery pack, etc.Additionally or alternatively, the battery pack can identify thehand-held power tool as a hammer drill, a drill/driver, an impactdriver, an impact wrench, a brushless power tool, a brushed power tool,a higher resistance power tool (e.g., capable of lower power output), alower resistance power tool (e.g., capable of higher power output), etc.

As illustrated in FIGS. 4 and 5 , the hammer drill 100 also includes,among other things, a control printed circuit board (“PCB”) 165, aswitching FET PCB 170, a switch 175 connected to the trigger 140, adrive mechanism 180, the chuck 130, and a brushless direct current(“BLDC”) motor 185. In some embodiments, the drive mechanism 180 caninclude a gear assembly, a mode selection mechanism, a clutch assembly,etc. The control PCB 165 is positioned near the terminal assembly 160and controls the operation of the hammer drill 100 based on sensed orstored characteristics and parameters of the hammer drill. For example,the control PCB 165 is operable to control the selective application ofpower to the motor 185. The switching FET PCB 170 includes a series ofswitching FETs 190 for controlling the application of power to the BLDCmotor 185 based on electrical signals received from the control PCB 165and a heat sink 195 (e.g., an aluminum, aluminum-alloy, copper, etc.,heat sink). In some embodiments, the switching FETs 190 are directlycoupled (i.e., directly physically and/or thermally coupled) to the heatsink 195 (e.g., directly on the heat sink, via copper tracings on a PCB,etc.). In other embodiments, the switching FETs 190 are not directlycoupled to the heat sink 195, but are in a heat transfer relationshipwith the heat sink 195. The switching FET PCB 170 includes, for example,six switching FETs 190 (only three are illustrated in the profile-viewsof FIGS. 4 and 5 ). The FETs have a low drain-to-source resistance, suchas below approximately 3.0 milli-Ohms. In some embodiments, thedrain-to-source resistance of the FETs is between approximately 1.4milli-Ohms and 2.0 milli-Ohms. In other embodiments, the drain-to-sourceresistance of the FETs has any value between approximately 1.0milli-Ohms and 10.0 milli-Ohms.

By using lower resistance FETs in combination with, for example, theheat sinking and airflow characteristics of the hand-held power tooldescribed below, the heat generated by switching FETs is capable ofbeing controlled and regulated more effectively by the hand-held powertool to enable increased drive currents to be passed through theswitching FETs and provided to the motor 185. For example, the Jouleheating associated with passing high currents to the motor 185 areproportional to the value of the current squared multiplied byresistance. By reducing the resistance between the battery pack and themotor 185, the amount of Joule heating that results from the motordrawing high currents is reduced. Thus, the hand-held power tool is lesssusceptible to thermal failure when the motor 185 draws high currents,and can generate greater output power. In some embodiments, the FETsare, for example, IRLB3034PbF FETs from International Rectifier, ElSegundo, Calif. The number of switching FETs included in a hand-heldpower tool is related to, for example, the desired commutation schemefor the motor. The embodiments of the hammer drill described herein arewith respect to a six-step commutation scheme that includes sixswitching FETS 190 and six stator coils (e.g., composed of copper). Inother embodiments, additional or fewer switching FETs and stator coilscan be employed (e.g., 4, 8, 12, 16, between 4 and 16, etc.).

The electronics illustrated in FIGS. 4 and 5 include multiple PCB'slocated in various portions of the hammer drill 100. The hammer drill100 can, however, include different PCB configurations than theconfiguration illustrated in FIGS. 4 and 5 . For example, the hammerdrill can include the “surfboard” PCB illustrated in and described withrespect to FIGS. 10-12 . The hammer drill 100 can also include the“doughnut” PCB illustrated in and described with respect to FIGS. 49 and50 . The differences between the various PCB configurations aredescribed below. For example, each PCB configuration may result in adifferent weight for the electronics package of the hammer drill 100.However, each of the PCB configurations described herein hasapproximately the same total weight. The PCB configuration can alsoaffect, for example, the location and number of external air vents, thelocation and size of heat sinks, etc., which can impact the performancecharacteristics of the hammer drill.

The drive mechanism 180 is operable to reduce the speed of a rotatingmotor shaft to a speed that is suitable for the hammer drill 100. Thedrive mechanism 180 is coupled to the chuck 130 for driving an outputdevice (e.g., a drill bit, etc.). The drive mechanism 180 is notdescribed in detail herein because the characteristics of the drivemechanism 180 can vary from one type of hand-held power tool to anotherdepending upon the particular action that the hand-held power tool isperforming (e.g., the action of an impact wrench is different from theaction of a drill/driver). However, the BLDC motor is described ingreater detail below. The hammer drill 100 also includes additionalinternal components and mechanisms illustrated in FIGS. 4 and 5 that arenot explicitly described herein but are known to those skilled in theart (e.g., a gear assembly, a clutch, etc.).

FIGS. 6 and 7 illustrate selected portions of the hammer drill 100. Forexample, FIGS. 6 and 7 illustrate the electronics and the motor of thehammer drill 100. Although the motor is described in greater detailbelow, for the sake of clarity and context, the motor 185 includes,among other things, a fan 200 (e.g., plastic, metal, etc.), bearings205, a stator 210 (described below), a rotor (described below), and ashaft 215. The fan 200 is operable to force air 220 (see FIG. 5 ) overthe switching FETs 190 of the switching FET PCB 170 to improve thedissipation of heat from the switching FETs 190. The air exits thehand-held power tool through the vents 145. The electronics include thecontrol PCB 165, the switching FET PCB 170, the switching FETS 190, thetrigger 140 and associated switch 175, the worklight 150, theforward/reverse switch 135, the heat sink 195, and a Hall effect PCB225, as well as assorted wires (e.g., 14AWG wires for providing powerfrom the battery pack to the motor) and other components for connection,protection, and operation of the hammer drill 100. In general, theelectronics include all portions of the hammer drill 100 minus thefollowing: the housing, the battery pack, mechanical components (e.g., agear assembly, a clutch, the chuck 130, etc.), and the motor 185. Theremaining portions of the hammer drill 100 are considered the“electronics” (e.g., PCBs, wires, switches, terminals, sensors, LEDs,etc.).

The hammer drill 100, for example, can be powered by an 18V batterypack. The hammer drill 100 can operate at two speeds (e.g., 0-550 RPM or0-1850 RPM), generate 725 in-lbs of maximum torque (i.e., stall torque),produce approximately 31,450 blows per minute (“BPM”), and weigh onlyapproximately 5.0 lbs with a ten-cell extra-capacity battery pack (e.g.,3.0 Ah), such as the M18™ XC High Capacity REDLITHIUM™ battery pack,manufactured and sold by Milwaukee Electric Tool, Milwaukee, Wis., orthe battery packs as described below. In some embodiments, the hammerdrill and extra-capacity battery pack weigh less than approximately 5.0lbs. In other embodiments, the hammer drill and the extra-capacitybattery pack weigh between approximately 4.0 lbs and approximately 5.0lbs, or between approximately 4.0 lbs and approximately 5.5 lbs.

If, for example, a five-cell regular-capacity battery pack were used topower the hammer drill 100, the hammer drill 100 can operate at twospeeds (e.g., 0-550 RPM or 0-1850 RPM), generate 650 in-lbs of maximumtorque (i.e., stall torque), produce approximately 31,450 BPM, and weighonly approximately 4.5 lbs with the five-cell regular-capacity batterypack (e.g., 1.5 Ah), such as the M18™ REDLITHIUM™ 2.0 compact batterypack, manufactured and sold by Milwaukee Electric Tool, Milwaukee, Wis.,of the battery packs as described below. In some embodiments, the hammerdrill and regular-capacity battery pack weigh less than approximately4.5 lbs. In other embodiments, the hammer drill and the regular-capacitybattery pack weigh between approximately 3.5 lbs and approximately 4.5lbs, or between approximately 3.5 lbs and approximately 5.0 lbs.

The cordless, hand-held power tool illustrated in FIGS. 8-12 is adrill/driver 300. The drill/driver 300 includes an upper main body 305,a handle portion 310, a battery pack receiving portion 315, a torqueadjustment dial or ring 320, an output drive device or mechanism 325, aforward/reverse selection button 330, a trigger 335, and air vents 340.The drill/driver 300 also includes a worklight 345, and the battery packreceiving portion 315 receives a portion of a battery pack (see FIGS.36-43 ) and includes a terminal assembly 350 including a plurality ofterminals. The number of terminals present in the receiving portion 315can vary based on the type of hand-held power tool. However, as anillustrative example, the receiving portion and the terminal assemblycan include a battery positive (“B+”) terminal, a battery negative(“B−”) terminal, a sense or communication terminal, an identificationterminal, etc. The outer portions or housing of the drill/driver 300(e.g., the main body 305 and the handle portion 310) are composed of adurable and light-weight plastic material. The drive mechanism(described below) is composed of a metal (e.g., steel) as is known inthe art.

The battery positive and battery negative terminals are operable toelectrically connect the battery pack to the hand-held power tool andprovide operational power (i.e., voltage and current) for the hand-heldpower tool from the battery pack to the hand-held power tool. The sensoror communication terminal is operable to provide for communication orsensing for the hand-held power tool of the battery pack. For example,the communication can include serial communication or a serialcommunication link, the transmission or conveyance of information fromone of the battery pack or the hand-held power tool to the other of thebattery pack or hand-held power tool related to a condition orcharacteristic of the battery pack or hand-held power tool (e.g., one ormore battery cell voltages, one or more battery pack voltages, one ormore battery cell temperatures, one or more battery pack temperatures,etc.).

The identification terminal can be used by the battery pack or thehand-held power tool to identify the other of the battery pack or thehand-held power tool. For example, the hand-held power tool can identifythe battery pack as a high capacity battery pack or a normal capacitybattery pack, as a lithium-based battery or a nickel-based battery, as abattery pack having a particular voltage (described below), a higherresistance battery pack, a lower resistance battery pack, etc.Additionally or alternatively, the battery pack can identify thehand-held power tool as a hammer drill, a drill/driver, an impactdriver, an impact wrench, a brushless power tool, a brushed power tool,a higher resistance power tool (e.g., capable of lower power output), alower resistance power tool (e.g., capable of higher power output), etc.

As illustrated in FIGS. 10-12 , the drill/driver 300 also includes,among other things, a surfboard PCB 355, a switch 360 connected to thetrigger 335, a drive mechanism 365, the chuck 325, and a BLDC motor 370.In some embodiments, the drive mechanism 365 can include a gearassembly, a mode selection mechanism, a clutch assembly, etc. Thesurfboard PCB 355 controls or regulates the power from the battery packin order to selectively provide power to the motor 370, and includesswitching FETs 405 for controlling the application of power to the BLDCmotor 370. The surfboard PCB 355 includes, for example, six switchingFETs 405. The FETs have a low drain-to-source resistance, such as belowapproximately 3.0 milli-Ohms. In some embodiments, the drain-to-sourceresistance of the FETs is between approximately 1.4 milli-Ohms and 2.0milli-Ohms. In other embodiments, the drain-to-source resistance of theFETs has any value between approximately 1.0 milli-Ohms and 10.0milli-Ohms.

By using lower resistance FETs in combination with, for example, theheat sinking and airflow characteristics of the hand-held power tooldescribed below, the heat generated by switching FETs is capable ofbeing controlled and regulated more effectively by the hand-held powertool to enable increased drive currents to be passed through theswitching FETs and provided to the motor 370. For example, the Jouleheating associated with passing high currents to the motor 370 areproportional to the value of the current squared multiplied byresistance. By reducing the resistance between the battery pack and themotor 370, the amount of Joule heating that results from the motordrawing high currents is reduced. Thus, the hand-held power tool is lesssusceptible to thermal failure when the motor 370 draws high currents.The FETs are, for example, IRLB3034 FETs or IRFS7437 FETs fromInternational Rectifier, El Segundo, Calif. The number of switching FETsincluded in a hand-held power tool is related to, for example, thedesired commutation scheme for the motor. The embodiments of thedrill/driver described herein is with respect to a six-step commutationscheme that includes six switching FETS 405 and six stator coils (e.g.,composed of copper). In other embodiments, additional or fewer switchingFETs and stator coils can be employed (e.g., 4, 8, 12, 16, between 4 and16, etc.).

The electronics illustrated in FIGS. 11 and 12 include a surfboard PCB355 located below the motor 370 of the drill/driver 300. Thedrill/driver 300 can, however, include different PCB configurations thanthe configuration illustrated in FIGS. 11 and 12 . For example, thedrill/driver can include the PCB configuration illustrated in anddescribed with respect to FIGS. 4 and 5 (e.g., a multi-PCB configurationor distributed PCB configuration). The drill/driver can also include the“doughnut” PCB illustrated in and described with respect to FIGS. 49 and50 . The differences between the various PCB configurations aredescribed below. For example, each PCB configuration may result in adifferent weight for the electronics package of the drill/driver 300.However, each of the PCB configurations described herein hasapproximately the same total weight. The PCB configuration can alsoaffect, for example, the location and number of external air vents, thelocation and size of heat sinks, etc., which can impact the performancecharacteristics of the drill/driver.

The drive mechanism 365 is operable to reduce the speed of a rotatingmotor shaft to a speed that is suitable for the drill/driver 300. Thedrive mechanism 365 is coupled to the chuck 325 for driving an outputdevice (e.g., a drill bit, etc.). The drive mechanism 365 is notdescribed in detail herein because the characteristics of the drivemechanism 365 can vary from one type of hand-held power tool to anotherdepending upon the particular action that the hand-held power tool isperforming (e.g., the action of an impact wrench is different from theaction of a drill/driver). However, the BLDC motor is described ingreater detail below. The drill/driver 300 also includes additionalinternal components and mechanisms illustrated in FIG. 10 that are notexplicitly described herein but are known to those skilled in the art(e.g., a gear assembly, a clutch, etc.).

FIGS. 11 and 12 illustrate selected portions of the drill/driver 300.For example, FIGS. 11 and 12 illustrate the electronics and the motor ofthe drill/driver 300. Although the motor is described in greater detailbelow, for the sake of clarity and context, the motor 370 includes,among other things, a fan 375 (e.g., plastic, metal, etc.), bearings380, a stator 385 (described below), a rotor (described below), and ashaft 390. The fan 375 is operable to force air 395 (see FIG. 10 ) overswitching FETs 405 of the surfboard PCB 355 to improve the dissipationof heat from the switching FETs 405. The air exits the hand-held powertool through the vents 340. The electronics includes the surfboard PCB355, the switching FETS 455, the trigger and associated switch 360, theworklight 345, the forward/reverse switch 330, a heat sink 400 (e.g., analuminum, aluminum-alloy, copper, etc., heat sink), and a Hall effectPCB 410, as well as assorted wires (e.g., 14AWG wires for providingpower from the battery pack to the motor) and other components forconnection, protection, and operation of the drill/driver 300 (e.g.,wires). In some embodiments, the switching FETs 405 are directly coupled(i.e., directly physically and/or thermally coupled) to the heat sink400 (e.g., directly on the heat sink, via copper tracings on a PCB,etc.). In other embodiments, the switching FETs 405 are not directlycoupled to the heat sink 400, but are in a heat transfer relationshipwith the heat sink 400. In general, the electronics include all portionsof the drill/driver 300 minus the following: the housing, the batterypack, mechanical components (e.g., a gear assembly, a clutch, the chuck325, etc.), and the motor 370. The remaining portions of thedrill/driver are considered the “electronics” (e.g., PCBs, wires,switches, terminals, sensors, LEDs, etc.).

The drill/driver 300, for example, can be powered by an 18V batterypack. The drill/driver 300 can operate at two speeds (e.g., 0-550 RPM or0-1850 RPM), generate 725 in-lbs of maximum torque (i.e., stall torque),and weigh only approximately 4.9 lbs with a ten-cell extra-capacitybattery pack (e.g., 3.0 Ah), such as the M18™ XC High CapacityREDLITHIUM™ battery pack, manufactured and sold by Milwaukee ElectricTool, Milwaukee, Wis., or the battery packs described below. In someembodiments, the drill/driver and extra-capacity battery pack weigh lessthan approximately 5.0 lbs. In other embodiments, the drill/driver andthe extra-capacity battery pack weigh between approximately 4.0 lbs andapproximately 5.0 lbs, or between approximately 4.0 lbs andapproximately 5.5 lbs.

If, for example, a regular-capacity battery pack were used to power thedrill/driver 300, the drill/driver 300 can operate at two speeds (e.g.,0-550 RPM or 0-1850 RPM), generate 650 in-lbs of maximum torque (i.e.,stall torque), and weigh only approximately 4.4 lbs with a five-cellregular-capacity battery pack (e.g., 1.5 Ah), such as the M18™REDLITHIUM™ 2.0 compact battery pack manufactured and sold by MilwaukeeElectric Tool, Milwaukee, Wis., or the battery packs described below. Insome embodiments, the drill/driver and regular-capacity battery packweigh less than approximately 4.5 lbs. In other embodiments, thedrill/driver and the regular-capacity battery pack weigh betweenapproximately 3.5 lbs and approximately 4.5 lbs, or betweenapproximately 3.5 lbs and approximately 5.0 lbs.

The cordless, hand-held power tool illustrated in FIGS. 13-17 is animpact wrench 500. The impact wrench 500 includes an upper main body505, a handle portion 510, a battery pack receiving portion 515, torqueand/or speed selection switches 520, an output drive device or mechanism525, a forward/reverse selection button 530, a trigger 535, and airvents 540. The impact wrench 500 also includes a worklight 545, and thebattery pack receiving portion 515 receives a portion of a battery pack(see FIGS. 36-43 ) and includes a terminal assembly 550 including aplurality of terminals. The number of terminals present in the receivingportion 515 can vary based on the type of hand-held power tool. However,as an illustrative example, the receiving portion and the terminalassembly can include a battery positive (“B+”) terminal, a batterynegative (“B−”) terminal, a sense or communication terminal, anidentification terminal, etc. The outer portions or housing of theimpact wrench 500 (e.g., the main body 505 and the handle portion 510)are composed of a durable and light-weight plastic material. The drivemechanism (described below) is composed of a metal (e.g., steel) as isknown in the art.

The battery positive and battery negative terminals are operable toelectrically connect the battery pack to the hand-held power tool andprovide operational power (i.e., voltage and current) for the hand-heldpower tool from the battery pack to the hand-held power tool. The sensoror communication terminal is operable to provide for communication orsensing for the hand-held power tool of the battery pack. For example,the communication can include serial communication or a serialcommunication link, the transmission or conveyance of information fromone of the battery pack or the hand-held power tool to the other of thebattery pack or hand-held power tool related to a condition orcharacteristic of the battery pack or hand-held power tool (e.g., one ormore battery cell voltages, one or more battery pack voltages, one ormore battery cell temperatures, one or more battery pack temperatures,etc.).

The identification terminal can be used by the battery pack or thehand-held power tool to identify the other of the battery pack or thehand-held power tool. For example, the hand-held power tool can identifythe battery pack as a high capacity battery pack or a normal capacitybattery pack, as a lithium-based battery or a nickel-based battery, as abattery pack having a particular voltage (described below), a higherresistance battery pack, a lower resistance battery pack, etc.Additionally or alternatively, the battery pack can identify thehand-held power tool as a hammer drill, a drill/wrench, an impactwrench, an impact wrench, a brushless power tool, a brushed power tool,a higher resistance power tool (e.g., capable of lower power output), alower resistance power tool (e.g., capable of higher power output), etc.

As illustrated in FIGS. 15-17 , the impact wrench 500 also includes,among other things, a surfboard PCB 555, a switch 560 connected to thetrigger 535, a drive mechanism 565, and a BLDC motor 570. In someembodiments, the drive mechanism 565 can include a gear assembly, a modeselection mechanism, a clutch assembly, etc. The surfboard PCB 555controls or regulates the power from the battery pack in order toselectively provide power to the motor 570, and includes switching FETs575 for controlling the application of power to the BLDC motor 570. Thesurfboard PCB 555 includes, for example, six switching FETs 575 and aheat sink 580 (e.g., an aluminum, aluminum-alloy, copper, etc., heatsink). The FETs have a low drain-to-source resistance, such as belowapproximately 3.0 milli-Ohms. In some embodiments, the drain-to-sourceresistance of the FETs is between approximately 1.4 milli-Ohms and 2.0milli-Ohms. In other embodiments, the drain-to-source resistance of theFETs has any value between approximately 1.0 milli-Ohms and 10.0milli-Ohms.

By using lower resistance FETs in combination with, for example, theheat sinking and airflow characteristics of the hand-held power tooldescribed below, the heat generated by switching FETs is capable ofbeing controlled and regulated more effectively by the hand-held powertool to enable increased drive currents to be passed through theswitching FETs and provided to the motor 570. For example, the Jouleheating associated with passing high currents to the motor 570 areproportional to the value of the current squared multiplied byresistance. By reducing the resistance between the battery pack and themotor 570, the amount of Joule heating that results from the motordrawing high currents is reduced. Thus, the hand-held power tool is lesssusceptible to thermal failure when the motor 570 draws high currents.The FETs are, for example, IRLB3034 FETs or IRFS7437 FETs fromInternational Rectifier, El Segundo, Calif. In some embodiments, theswitching FETs 575 are directly coupled (i.e., directly physicallyand/or thermally coupled) to the heat sink 580 (e.g., directly on theheat sink, via copper tracings on a PCB, etc.). In other embodiments,the switching FETs 575 are not directly coupled to the heat sink 580,but are in a heat transfer relationship with the heat sink 580. Thenumber of switching FETs included in a hand-held power tool is relatedto, for example, the desired commutation scheme for the motor. Theembodiments of the impact wrench described herein are with respect to asix-step commutation scheme that includes six switching FETS 575 and sixstator coils (e.g., composed of copper). In other embodiments,additional or fewer switching FETs and stator coils can be employed(e.g., 4, 8, 12, 16, between 4 and 16, etc.).

The electronics illustrated in FIGS. 16 and 17 include a surfboard PCB555 located below the motor 570 of the impact wrench 500. The impactwrench 500 can, however, include different PCB configurations than theconfiguration illustrated in FIGS. 11 and 12 . For example, the impactwrench can include the PCB configuration illustrated in and describedwith respect to FIGS. 4 and 5 (e.g., a multi-PCB configuration ordistributed PCB configuration). The impact wrench can also include the“doughnut” PCB illustrated in and described with respect to FIGS. 49 and50 . The differences between the various PCB configurations aredescribed below. For example, each PCB configuration may result in adifferent weight for the electronics package of the impact wrench 500.However, each of the PCB configurations described herein hasapproximately the same total weight. The PCB configuration can alsoaffect, for example, the location and number of external air vents, thelocation and size of heat sinks, etc., which can impact the performancecharacteristics of the impact wrench 500.

The drive mechanism 565 is operable to reduce the speed of a rotatingmotor shaft to a speed that is suitable for the impact wrench 500. Thedrive mechanism 565 is coupled to the output drive device 525 fordriving an output device. The drive mechanism 565 is not described indetail herein because the characteristics of the drive mechanism 565 canvary from one type of hand-held power tool to another depending upon theparticular action that the hand-held power tool is performing (e.g., theaction of an impact wrench is different from the action of adrill/driver). However, the BLDC motor is described in greater detailbelow. The impact wrench 500 also includes additional internalcomponents and mechanisms illustrated in FIG. 15 that are not explicitlydescribed herein but are known to those skilled in the art.

FIGS. 16 and 17 illustrate selected portions of the impact wrench 500.For example, FIGS. 16 and 17 illustrate the electronics and the motor ofthe impact wrench 500. Although the motor is described in greater detailbelow, for the sake of clarity and context, the motor 570 includes,among other things, a fan 585 (e.g., plastic, metal, etc.), bearings590, a stator 595 (described below), a rotor (described below), and ashaft 600. The fan 585 is operable to force air 605 (see FIG. 15 ) overthe switching FETs 575 of the surfboard PCB 555 to improve thedissipation of heat from the switching FETs 575. The air exits thehand-held power tool through the vents 540. The electronics include thesurfboard PCB 555, the switching FETS 575, the trigger 535 andassociated switch 560, the worklight 545, the forward/reverse switch530, the heat sink 580, and a Hall Effect PCB 610, as well as assortedwires (e.g., 14AWG wires for providing power from the battery pack tothe motor) and other components for connection, protection, andoperation of the impact wrench 500. In general, the electronics includeall portions of the impact wrench 500 minus the following: the housing,the battery pack, mechanical components (e.g., a gear assembly, aclutch, etc.), and the motor 570. The remaining portions of the impactwrench are considered the “electronics” (e.g., PCBs, wires, switches,terminals, sensors, LEDs, etc.).

The impact wrench 500, for example, can be powered by an 18V batterypack. The impact wrench 500 can operate at speeds of, for example,approximately 0-1800 RPM, generate 1100 ft-lbs of maximum torque (i.e.,stall torque), and weigh only approximately 3.5 lbs with a ten-cellextra-capacity battery pack (e.g., 3.0 Ah), such as the M18™ XC HighCapacity REDLITHIUM™ battery pack, manufactured and sold by MilwaukeeElectric Tool, Milwaukee, Wis., or the battery packs described below. Insome embodiments, the impact wrench 500 and extra-capacity battery packweigh less than approximately 3.5 lbs. In other embodiments, the impactwrench 500 and the extra-capacity battery pack weigh betweenapproximately 3.0 lbs and approximately 4.0 lbs, or betweenapproximately 3.0 lbs and approximately 4.5 lbs.

If, for example, a five-cell regular-capacity battery pack were used topower the impact wrench 500, the impact wrench 500 can operate at speedsof, for example, approximately 0-1800 RPM, generate 1100 ft-lbs ofmaximum torque (i.e., stall torque), and weigh only approximately 3.0lbs with a five-cell regular-capacity battery pack (e.g., 1.5 Ah), suchas the M18™ REDLITHIUM™ 2.0 compact battery pack, manufactured and soldby Milwaukee Electric Tool, Milwaukee, Wis., or the battery packs asdescribed below. In some embodiments, the impact wrench 500 andregular-capacity battery pack weigh less than approximately 3.0 lbs. Inother embodiments, the impact wrench 500 and the regular-capacitybattery pack weigh between approximately 2.5 lbs and approximately 3.5lbs, or between approximately 2.5 lbs and approximately 4.0 lbs.

The cordless, hand-held power tool illustrated in FIGS. 18-22 is animpact driver 700. The impact driver 700 includes an upper main body705, a handle portion 710, a battery pack receiving portion 715, torqueand/or speed selection switches 720, an output drive device or mechanism725, a forward/reverse selection button 730, a trigger 735, a belt clip740 (optionally included on the hammer drill 100, the drill/driver 300,and the impact wrench 500), and air vents 745. The impact driver 700also includes a worklight 750. The battery pack receiving portion 715receives a portion of a battery pack (see FIGS. 36-43 ) and includes aterminal assembly 755 including a plurality of terminals. The number ofterminals present in the receiving portion 715 can vary based on thetype of hand-held power tool. However, as an illustrative example, thereceiving portion and the terminal assembly can include a batterypositive (“B+”) terminal, a battery negative (“B−”) terminal, a sense orcommunication terminal, an identification terminal, etc. The outerportions or housing of the impact driver 700 (e.g., the main body 705and the handle portion 710) are composed of a durable and light-weightplastic material. The drive mechanism (described below) is composed of ametal (e.g., steel) as is known in the art.

The battery positive and battery negative terminals are operable toelectrically connect the battery pack to the hand-held power tool andprovide operational power (i.e., voltage and current) for the hand-heldpower tool from the battery pack to the hand-held power tool. The sensoror communication terminal is operable to provide for communication orsensing for the hand-held power tool of the battery pack. For example,the communication can include serial communication or a serialcommunication link, the transmission or conveyance of information fromone of the battery pack or the hand-held power tool to the other of thebattery pack or hand-held power tool related to a condition orcharacteristic of the battery pack or hand-held power tool (e.g., one ormore battery cell voltages, one or more battery pack voltages, one ormore battery cell temperatures, one or more battery pack temperatures,etc.).

The identification terminal can be used by the battery pack or thehand-held power tool to identify the other of the battery pack or thehand-held power tool. For example, the hand-held power tool can identifythe battery pack as a high capacity battery pack or a normal capacitybattery pack, as a lithium-based battery or a nickel-based battery, as abattery pack having a particular voltage (described below), a higherresistance battery pack, a lower resistance battery pack, etc.Additionally or alternatively, the battery pack can identify thehand-held power tool as a hammer drill, a drill/driver, an impactdriver, an impact driver, a brushless power tool, a brushed power tool,a higher resistance power tool (e.g., capable of lower power output), alower resistance power tool (e.g., capable of higher power output), etc.

As illustrated in FIGS. 20-22 , the impact driver 700 also includes,among other things, a surfboard PCB 760, a switch 765 connected to thetrigger 735, a drive mechanism 770, and a BLDC motor 775. In someembodiments, the drive mechanism 770 can include a gear assembly, a modeselection mechanism, a clutch assembly, etc. The surfboard PCB 760controls or regulates the power from the battery pack in order toselectively provide power to the motor 775, and includes switching FETs780 for controlling the application of power to the BLDC motor 775. Thesurfboard PCB 760 includes, for example, six switching FETs 780 and aheat sink 785 (e.g., an aluminum, aluminum-alloy, copper, etc., heatsink). The FETs have a low drain-to-source resistance, such as belowapproximately 3.0 milli-Ohms. In some embodiments, the drain-to-sourceresistance of the FETs is between approximately 1.4 milli-Ohms and 2.0milli-Ohms. In other embodiments, the drain-to-source resistance of theFETs has any value between approximately 1.0 milli-Ohms and 10.0milli-Ohms.

By using lower than typical resistance FETs in combination with, forexample, the heat sinking and airflow characteristics of the hand-heldpower tool described below, the heat generated by switching FETs iscapable of being controlled and regulated more effectively by thehand-held power tool to enable increased drive currents to be passedthrough the switching FETs 780 and provided to the motor 775. Forexample, the Joule heating associated with passing high currents to themotor 775 are proportional to the value of the current squaredmultiplied by resistance. By reducing the resistance between the batterypack and the motor 775, the amount of Joule heating that results fromthe motor drawing high currents is reduced. Thus, the hand-held powertool is less susceptible to thermal failure when the motor 775 drawshigh currents. The FETs are, for example, IRLB3034 FETs or IRFS7437 FETsfrom International Rectifier, El Segundo, Calif. In some embodiments,the switching FETs 780 are directly coupled (i.e., directly physicallyand/or thermally coupled) to the heat sink 785 (e.g., directly on theheat sink, via copper tracings on a PCB, etc.). In other embodiments,the switching FETs are not directly coupled to the heat sink 785, butare in a heat transfer relationship with the heat sink 785. The numberof switching FETs included in a hand-held power tool is related to, forexample, the desired commutation scheme for the motor. The embodimentsof the impact driver described herein are with respect to a six-stepcommutation scheme that includes six switching FETs 780 and six statorcoils (e.g., composed of copper). In other embodiments, additional orfewer switching FETs and stator coils can be employed (e.g., 4, 8, 12,16, between 4 and 16, etc.).

The electronics illustrated in FIGS. 21 and 22 include a surfboard PCB760 located below the motor 775 of the impact driver 700. The impactdriver 700 can, however, include different PCB configurations that theconfiguration illustrated in FIGS. 11 and 12 . For example, the impactdriver can include the PCB configuration illustrated in and describedwith respect to FIGS. 4 and 5 (e.g., a multi-PCB configuration ordistributed PCB configuration). The impact driver can also include the“doughnut” PCB illustrated in and described with respect to FIGS. 49 and50 . The differences between the various PCB configurations aredescribed below. For example, each PCB configuration may result in adifferent weight for the electronics package of the impact driver 700.However, each of the PCB configurations described herein hasapproximately the same total weight. The PCB configuration can alsoaffect, for example, the location and number of external air vents, thelocation and size of heat sinks, etc., which can impact the performancecharacteristics of the impact driver.

The drive mechanism 770 is operable to reduce the speed of a rotatingmotor shaft to a speed that is suitable for the impact driver 700. Thedrive mechanism 770 is coupled to the output drive device 725 fordriving an output device (e.g., a drill bit, etc.). The drive mechanism770 is not described in detail herein because the characteristics of thedrive mechanism 770 can vary from one type of hand-held power tool toanother depending upon the particular action that the hand-held powertool is performing (e.g., the action of an impact driver is differentfrom the action of a drill/driver). However, the BLDC motor is describedin greater detail below. The impact driver 700 also includes additionalinternal components and mechanisms illustrated in FIG. 20 that are notexplicitly described herein but are known to those skilled in the art(e.g., a hammer mechanism, an anvil, etc.).

FIGS. 21 and 22 illustrate selected portions of the impact driver 700.For example, FIGS. 21 and 22 illustrate the electronics and the motor ofthe impact driver 700. Although the motor 775 is described in greaterdetail below, for the sake of clarity and context, the motor 775includes, among other things, a fan 790 (e.g., plastic, metal, etc.),bearings 795, a stator 800 (described below), a rotor (described below),and a shaft 805. The fan 790 is operable to force air 810 (see FIG. 20 )over the switching FETs 780 of the surfboard PCB 760 to improve thedissipation of heat from the switching FETs 780. The air exits thehand-held power tool through the vents 745. The electronics include thesurfboard PCB 760, the switching FETS 780, the trigger 735 andassociated switch 765, the worklight 750, the forward/reverse switch730, the heat sink 785, and a Hall Effect PCB 815, as well as assortedwires (e.g., 14AWG wires for providing power from the battery pack tothe motor) and other components for connection, protection, andoperation of the impact driver 700. In general, the electronics includeall portions of the impact driver 700 minus the following: the housing,the battery pack, mechanical components (e.g., a gear assembly, aclutch, etc.), and the motor 775. The remaining portions of the impactdriver 700 are considered the “electronics” (e.g., PCBs, wires,switches, terminals, sensors, LEDs, etc.).

The impact driver 700, for example, can be powered by an 18V batterypack. The impact driver 700 can operate at speeds between, for example,0-2900 RPM, generate 1600 in-lbs of maximum torque (i.e., stall torque),produce approximately 0-3600 impacts per minute (“IPM”), and weigh onlyapproximately 3.6 lbs with a ten-cell extra-capacity battery pack (e.g.,3.0 Ah), such as the M18™ XC High Capacity REDLITHIUM™ battery pack,manufactured and sold by Milwaukee Electric Tool, Milwaukee, Wis., orthe battery packs as described below. In some embodiments, the impactdriver 700 and extra-capacity battery pack weigh less than approximately4.0 lbs. In other embodiments, the impact driver and the extra-capacitybattery pack weigh between approximately 3.0 lbs and approximately 3.8lbs, or between approximately 3.0 lbs and approximately 4.0 lbs.

If a five-cell regular-capacity battery pack were to be used to powerthe impact driver, the impact driver 700 can operate at speeds between,for example, 0-2900 RPM, generate 1600 in-lbs of maximum torque (i.e.,stall torque), produce approximately 0-3600 impacts per minute (“IPM”),and weigh only approximately 3.0 lbs with a five-cell regular-capacitybattery pack (e.g., 1.5 Ah), such as the M18™ REDLITHIUM™ 2.0 compactbattery pack, manufactured and sold by Milwaukee Electric Tool,Milwaukee, Wis., or the battery packs as described below. In someembodiments, the impact driver 700 and regular-capacity battery packweigh less than approximately 3.0 lbs. In other embodiments, the impactdriver and the regular-capacity battery pack weigh between approximately2.5 lbs and approximately 3.5 lbs, or between approximately 2.5 lbs andapproximately 4.0 lbs.

Each of the above described cordless, hand-held power tools (i.e., thehammer drill 100, the drill/driver 300, the impact wrench 500, and theimpact driver 700), as well as additional hand-held power tools such asa saw, an angle grinder, a bandsaw, a belt sander, a chainsaw, acircular saw, a concrete saw, a disc sander, a floor sander, a jigsaw, arotary hammer, a grinder, a nail gun, a reciprocating saw (e.g.,one-handed reciprocating saw or two-handed reciprocating saw), a router,etc., can include a BLDC motor 900 as illustrated in and described withrespect to FIGS. 23-35 (introduced previously above as motors 185, 370,570, and 775). In other embodiments, the motor 900 and electronicsdescribed herein can be implemented with a power source (e.g., a batterypack) for a variety of non-hand-held power tools, such as a magneticbase drill stand, a miter saw, a scroll saw, etc. In such embodiments,the performance of the motor (e.g., short-run and long-run performancecharacteristics) is the same or similar to that of the hand-held powertools described herein.

The motor 900 illustrated in FIGS. 23-35 is a BLDC motor and includes astator 905, a rotor 910 (see FIG. 32 ), a first motor bearing 915, asecond motor bearing 920, a fan 925 (e.g., plastic, metal, etc.), afirst stator end connecting portion 930, and a second stator endconnecting portion 935. The stator 905 includes a plurality of coils 940and stator laminations. In the illustrated embodiment, the motor 900includes six stator coils 940 (i.e., three pairs of stator coils). Thestator coils 940 (e.g., composed of copper) are wrapped around thelaminations of the stator 905 formed between the first end connectionportion 930 and the second end connection portion 935. As describedabove, the motor 900 can include a different number of stator coils thanthe illustrated six stator coils (e.g., between 4 and 16 stator coils).The design and construction of the motor 900 is such that itsperformance characteristics are in balance with the control electronicsand battery pack described herein in order to maximize the output powercapability of the hand-held power tool. The motor 900 is composedprimarily of steel (e.g., steel laminations), permanent magnets (e.g.,sintered Neodymium Iron Boron), and copper (e.g., copper stator coils).The size and dimensions related to various motor features describedherein are provided with respect to exemplary ranges of values formaximizing the performance of the motor (e.g., maximum long and shortduration output power, torque, etc.). The characteristics and featuresof the motor 900 described herein dictate the performance capabilitiesof the motor 900. As such, values and ranges of values for thesefeatures and characteristics have been provided which, when implementedin combination with the battery pack and control electronics alsodescribed herein, maximize both short-run and long-run output power ofthe hand-held power tool.

The motor stator 905 includes an outer stator diameter, D_(s), an innerstator diameter, D_(IS), and a stator length, L_(S) (i.e., active motorlength). For example, the outer stator diameter can have a value of, forexample, approximately 40 millimeters (“mm”), 45 mm, 50 mm, or 60 mm.These exemplary stator outer diameters are illustrative of practicalouter stator diameters for a hand-held power tool including a BLDCmotor. However, other outer stator diameters for the motor 900 are alsopossible. For example, outer stator diameters between approximately 40mm and approximately 60 mm can be used. In other embodiments, outerstator diameters of less than approximately 40 mm (e.g., betweenapproximately 20 mm and approximately 40 mm) or greater thanapproximately 60 mm (e.g., between approximately 60 mm and approximately80 mm) can also be used.

The inner stator diameter of the motor 900 can also have a variety ofvalues. For example, the inner stator diameter is dependent upon, atleast in part, the outer stator diameter of the motor. For a 40 mm outerstator diameter, the inner stator diameter is approximately 23 mm. For a45 mm outer stator diameter, the inner stator diameter is approximately25 mm. For a 50 mm outer stator diameter, the inner stator diameter isapproximately 27 mm. For a 60 mm outer stator diameter, the inner statordiameter is approximately 33 mm. As described above with respect to theouter stator diameter, the inner stator diameter can also have othervalues. For example, the inner stator diameter of the motor 900 can havea value of between approximately 20 mm and 40 mm. Additionally oralternatively, the inner stator diameter can have a value thatrepresents a percentage of the outer stator diameter (e.g., betweenapproximately 30% and approximately 60% of the outer stator diameter).As an illustrative example, a motor having an outer stator diameter ofapproximately 50 mm can have an inner stator diameter of approximately27 mm, which represents an inner stator diameter that is approximately54% of the outer stator diameter.

The stator length, L_(S), has a value of between approximately 19 mm andapproximately 29 mm. For example, in one embodiment, the stator length,L_(S), is approximately 24 mm. In other embodiments, the stator length,L_(S), has any value between approximately 12 mm and 36 mm.

The rotor 910 of the motor 900 includes a cylindrically-shaped rotorportion 945, a plurality of permanent magnets 950 set or embedded withinthe rotor portion 945, and a rotor shaft 955. The rotor shaft 955 has arotor shaft length, L_(R/S), and a shaft diameter D_(RS), and the rotorportion 945 has a rotor portion length or magnet length, L_(M). In theillustrated embodiment, the rotor 910 has a rotor diameter, D_(R), themagnet length, L_(M), a bearing-to-bearing length, L_(BB), and the rotoror rotor shaft length, L_(R/S) (i.e., total motor length). Theillustrated BLDC motor is, for example, approximately 30%-40% moreefficient than conventional motors for hand-held power tools. Forexample, the motor 900 does not have power losses resulting frombrushes. The motor also combines the removal of steel from the rotor(i.e., in order to include the plurality of permanent magnets) andwindings of copper in the stator coils to increase the power density ofthe motor (i.e., removing steel from the rotor and adding more copper inthe stator windings can increase the power density of the motor). Motoralterations such as these allow the motor 900 having the characteristicsdescribed herein to produce more power than a conventional motor of thesame length, or, alternatively, to produce the same or more power from amotor smaller than the convention motors for hand-held power tools.

In some embodiments, the rotor diameter, D_(R), has a value of betweenapproximately 23 mm and approximately 29 mm. For example, in oneembodiment, the rotor diameter, D_(R), is approximately 26 mm. In otherembodiments, the rotor diameter, D_(R), has any value betweenapproximately 20 mm and 30 mm. In some embodiments, the rotor length,L_(R), has a value of between approximately 60 mm and approximately 70mm. For example, in one embodiment, the rotor length, L_(R), isapproximately 65 mm. In other embodiments, the rotor length, L_(R), hasany value between approximately 55 mm and 75 mm. In some embodiments,the bearing-to-bearing length, L_(BB), has a value of betweenapproximately 40 mm and approximately 50 mm. For example, in oneembodiment, the bearing-to-bearing length, L_(BB), is approximately 46mm. In other embodiments, the bearing-to-bearing length, L_(BB), has anyvalue between approximately 43 mm and 49 mm. In some embodiments, therotor shaft diameter, D_(S), has a value of between approximately 3 mmand approximately 7 mm. For example, in one embodiment, the rotor shaftdiameter, D_(S), is approximately 5 mm. In other embodiments, the rotorshaft diameter, D_(S), has any value between approximately 4 mm and 6mm. In some embodiments, the magnet length, L_(M), has a value ofbetween approximately 25 mm and approximately 30 mm. For example, in oneembodiment, the magnet length, L_(M), is approximately 28 mm. In otherembodiments, the magnet length, L_(M), has any value betweenapproximately 16 mm and 36 mm.

The motor 900 described above receives power (i.e., voltage and current)from a battery pack, such as the battery pack 1000 illustrated in FIGS.36-40 for powering the cordless, hand-held power tools 100, 300, 500,and 700. The battery pack 1000 is connectable to and supportable by thecordless, hand-held power tools 100, 300, 500, and 700. As shown inFIGS. 36-38 , the battery pack 1000 includes a housing 1005 and at leastone rechargeable battery cell 1010 (shown in FIGS. 39 and 40 ) supportedby the housing 1005. The battery pack 1000 also includes a supportportion 1015 for supporting the battery pack 1000 on and coupling thebattery pack 1000 to a hand-held power tool, a coupling mechanism 1020for selectively coupling the battery pack to, or releasing the batterypack 1000 from, a hand-held power tool. In the illustrated embodiment,the support portion 1015 is connectable to a complementary supportportion on the hand-held power tool (e.g., the battery pack receivingportion 115, 315, 515, and 715).

The battery pack 1000 includes a plurality of terminals 1025 of aterminal assembly within the support portion 1015 and operable toelectrically connect the battery cells 1010 to a PCB 1030 within thebattery pack 1000. The plurality of terminals 1025 includes, forexample, a positive battery terminal, a ground terminal, and a senseterminal. The battery pack 1000 is removably and interchangeablyconnected to a hand-held power tool to provide operational power to thehand-held power tool. The terminals 1025 are configured to mate withcorresponding power terminals extending from a hand-held power tool(e.g., within the battery pack receiving portion 115, 315, 515, and715). The battery pack 1000 substantially encloses and covers theterminals on the hand-held power tool when the pack 1000 is positionedwithin the battery pack receiving portion 115, 315, 515, and 715. Thatis, the battery pack 1000 functions as a cover for the opening andterminals of the hand-held power tool. Once the battery pack 1000 isdisconnected from the hand-held power tool, the terminals on thehand-held power tool are generally exposed to the surroundingenvironment. In this illustrated embodiment, the battery pack 1000 isdesigned to substantially follow the contours of the hand-held powertool to match the general shape of the outer casing of the handle of thehand-held power tool, and the battery pack 1000 generally increases(e.g., extends) the length of the grip of the tool (i.e., the portion ofthe power tool below the main body).

The illustrated battery pack 1000 includes 10 battery cells 1010. Inother embodiments, the battery pack 1000 can have more or fewer batterycells 1010. The battery cells can be arranged in series, parallel, or aseries-parallel combination. For example, the battery pack can include atotal of 10 battery cells configured in a series-parallel arrangement offive sets of two series-connected cells. The series-parallel combinationof battery cells allows for an increased voltage and an increasedcapacity of the battery pack. In some embodiments, the battery pack 1000includes five series-connected battery cells. In other embodiments, thebattery pack 1000 includes a different number of battery cells (e.g.,between 3 and 12 battery cells) connected in series, parallel, or aseries-parallel combination in order to produce a battery pack having adesired combination of nominal battery pack voltage and batterycapacity.

The illustrated battery cells 1010 are, for example, cylindrical 18650battery cells (18 mm diameter and 65 mm length), such as theINR18650-15M lithium-ion rechargeable battery cell manufactured and soldby Samsung SDI Co., Ltd. of South Korea. Each battery cell includes acell axis 1035, a cell length, L_(C), and a cell diameter, D_(C), asillustrated in FIGS. 39 and 40 . In other embodiments, the battery cells1010 are, for example, cylindrical 14500 battery cells (14 mm diameterand 50 mm length), 14650 battery cells (14 mm diameter and 65 mmlength), 17500 battery cells (17 mm diameter and 50 mm length), 17670battery cells (17 mm diameter and 67 mm length), 18500 battery cells (18mm diameter and 50 mm length), 26650 battery cells (26 mm diameter and65 mm length), 26700 battery cells (26 mm diameter and 70 mm length),etc. Each battery cell 1010 can be generally cylindrical and can extendalong the cell axis 1035 parallel to the cylindrical outer cell wall.Also, in the battery pack 1000, each battery cell 1010 can have a celllength, L_(C), which is greater than or equal to two times the celldiameter, D_(C). In some embodiments, the battery cells arelithium-based prismatic battery cells (e.g., between 1.5 Ah-5.0 Ah inbattery capacity) having dimensions of, for example, approximately 50 mmto approximately 80 mm in length, approximately 60 mm to approximately90 mm in width, and approximately 3 mm to approximately 8 mm in height.The prismatic battery cells can be implemented using, for example, awound configuration, a wound and flattened configuration, a wound andfolded configuration, or a layered and folded configuration.

The battery cells 1010 are lithium-based battery cells having achemistry of, for example, lithium-cobalt (“Li—Co”), lithium-manganese(“Li—Mn”), or Li—Mn spinel. In some embodiments, the battery cells 1010have other suitable lithium or lithium-based chemistries, such as alithium-based chemistry that includes manganese, etc. The battery cellswithin the battery pack 1000 provide operational power (e.g., voltageand current) to the power tools. In one embodiment, each battery cell1010 has a nominal voltage of approximately 3.6V, such that the batterypack has a nominal voltage of approximately 18V. In other embodiments,the battery cells have different nominal voltages, such as, for example,between 3.6V and 4.2V, and the battery pack has a different nominalvoltage, such as, for example, 10.8V, 12V, 14.4V, 24V, 28V, 36V, between10.8V and 36V, etc. The battery cells also have a capacity of, forexample, approximately between 1.0 ampere-hours (“Ah”) and 5.0 Ah. Inexemplary embodiments, the battery cells have capacities ofapproximately, 1.5 Ah, 2.4 Ah, 3.0 Ah, 4.0 Ah, between 1.5 Ah and 5.0Ah, etc.

The battery cells 1010 are arranged and spaced apart form one another bythe battery pack 1000 (e.g., each cell is provided in an individual cellreceiving area 1040 within the battery pack 1000 that spaces each cellapart) to reduce the cell-to-cell heat transfer between the batterycells 1010 and to improve the collection and removal of heat from thebattery cells 1010. In this manner, the battery cells 1010 may be ableto be maintained in an appropriate temperature operating range (e.g.,below 60° C.) for longer durations of use. The battery cells 1010 arealso arranged to provide an efficient use of space and to maintain arelatively small pack size.

The illustrated battery cells 1010 are optimized to have a low internalresistance and, as a result, and increased discharge current capability.For example, cylindrical (i.e., jelly-roll) type battery cells includethree main components: an anode or negative electrode; a cathode orpositive electrode; and an electrolyte. The anode gives up electrons tothe external circuit and is oxidized during the electrochemicalreaction. The cathode accepts electrons from the external circuit and isreduced during the electrochemical reaction. The electrolyte provides amedium for transferring charge (i.e., as ions) inside the cell betweenthe anode and the cathode. Typical lithium-based cylindrical batterycells also include, among other things, the cathode and the anode asdescribed above, a cathode lead for connecting to the positive terminalof the battery cell, an anode lead for connecting to the negativeterminal of the battery cell, a separator (i.e., a non-aqueouselectrolyte), an outer can for housing the cathode, anode, andseparator, a top cover (e.g., which can be crimped to the can to sealthe battery cell), and a gasket for providing a seal between the can andthe top cover. The battery cells 1010 can also include safety devices,such as, for example, a positive temperature coefficient (“PTC”) devicewithin each battery cell.

The performance of the battery cells 1010 can be improved in a varietyof ways. As an illustrative example, in order to increase the dischargecurrent that the battery cells are capable of producing, the size of theelectrodes (i.e., anode and cathode) is increased in order to increasethe reaction surfaces between the electrodes and minimize the internalresistance of the battery cell. For example, making the battery cellstaller (i.e., cell length) and wider (i.e., cell diameter) can increasethe reaction area of the electrodes. Variations in battery cellcharacteristics such as porosity, the thickness of the separator, thethickness of current collectors, etc., can also affect the internalresistance of the battery cells and be optimized for a particularapplication. The basic design and assembly of the illustrated batterycells 1010 is know in the art. For example, details of the constructionof cylindrical battery cells is described in the “Handbook ofBatteries,” third edition, by David Linden and Thomas Reddy, 2002.

The illustrated battery cells have been manufactured using, for example,the above described techniques to provide battery cells having a lowinternal resistance and increased discharge capability, whilemaintaining durability, cycle life, calendar life, etc. In someembodiments, the impedance of the battery pack 1000 is less thanapproximately 600 milli-Ohms. In other embodiments the impedance of thebattery pack is between approximately 400 milli-Ohms and approximately600 milli-Ohms. In some embodiments, the battery cells 1010 are capableof producing an average long-run discharge current of, for example,greater than or equal to approximately 25 amperes or betweenapproximately 20 amperes and approximately 40 amperes. The averagelong-run discharge current (or torque, output power, speed, etc.) of thebattery cells is the average current capable of being discharged by thebattery cells when the battery pack is operated through a completedischarge cycle (e.g., continuously from a fully-charged level until thebattery pack reaches a low-voltage cutoff). In other embodiments, theaverage discharge current capable of being produced by the battery cells1010 is between approximately 28 amperes and approximately 32 amperes.The battery cells 1010 are also capable of higher short-run currents (aprocess and time period for determining these values is describedbelow). For example, the battery cells are capable of producing anaverage short-run discharge current of greater than or equal toapproximately 55 amperes or between approximately 55 amperes andapproximately 75 amperes. In other embodiments, the average dischargecurrent capable of being produced by the battery cells 1010 is betweenapproximately 20 amperes and approximately 75 amperes.

FIGS. 41-43 illustrate another battery pack 1100 that is configured tobe used with hand-held power tools such as those described above. In theembodiment illustrated in FIGS. 41-43 , the battery pack 1100 has thesame battery cells as those described above with respect to the batterypack 1000 (illustrated as battery cells 1115 in this embodiment). Thebattery pack 1100 is removably and interchangeably connected to ahand-held power tool to provide operational power to the hand-held powertool.

The battery pack 1100 includes a casing 1105, an outer housing 1110coupled to the casing 1105, and a plurality of battery cells 1115 (seeFIG. 42 ) positioned within the casing 1105. The casing 1105 is shapedand sized to fit within an opening and cavity in a hand-held power tool.For example, a recess for receiving the battery pack 1100 similar tothose disclosed in the devices in U.S. Pat. No. 8,251,157, issued Aug.28, 2012 and entitled “BATTERY PACK FOR USE WITH A POWER TOOL AND ANON-MOTORIZED SENSING TOOL,” the entire content of which is herebyincorporated by reference, can be used. The casing 1105 includes an endcap 1120 to substantially enclose the battery cells 1115 within thecasing 1105. The illustrated end cap 1120 includes two power terminals1125 configured to mate with corresponding power terminals extendingfrom a hand-held power tool. In other embodiments, the end cap 1120 mayinclude terminals that extend from the battery pack 1100 and areconfigured to be received in receptacles supported by a hand-held powertool. The end cap 1120 also includes sense or communication terminals1130 (shown in FIG. 43 ) that are configured to mate with correspondingterminals from a hand-held power tool. The casing 1105 and thereceptacles substantially enclose and cover the terminals on the toolwhen the pack 1100 is positioned within the opening. That is, thebattery pack 1100 functions as a cover for the opening and terminals ofthe hand-held power tool. Once the battery pack 1100 is disconnectedfrom the hand-held power tool and the casing 1105 is removed from theopening, the battery terminals on the hand-held power tool are generallyexposed to the surrounding environment.

The outer housing 1110 is coupled to an end of the casing 1105substantially opposite the end cap 1120 and surrounds a portion of thecasing 1105. In the illustrated construction, when the casing 1105 isinserted into or positioned at least partially within the correspondingopening in the hand-held power tool, the outer housing 1110 generallyaligns with an outer surface of the hand-held power tool. In thisembodiment, the outer housing 1110 is designed to substantially followthe contours of the hand-held power tool to match the general shape ofthe outer casing of the handle of the hand-held power tool. In someembodiments, the casing 1105 is at least partially inserted into a gripof a hand-held power tool. In such embodiments, the outer housing 1110generally increases (e.g., extends) the length of the grip of the tool(i.e., the portion of the power tool below the main body).

In the illustrated embodiment, two actuators 1135 (only one of which isshown) and two tabs 1140 are formed in the outer housing 1110 of thebattery pack 1100. The actuators 1135 and the tabs 1140 define acoupling mechanism to releasably secure the battery pack 1100 tohand-held power tool. Each tab 1140 engages a corresponding recessformed in a hand-held power tool to secure the battery pack 1100 inplace. The tabs 1140 are normally biased away from the casing 1105(i.e., away from each other) due to the resiliency of the materialforming the outer housing 1110. Actuating (e.g., depressing) theactuators 1135 moves the tabs 1140 toward the casing 1105 (i.e., towardeach other) and out of engagement with the recesses such that thebattery pack 1100 may be pulled out of the opening and away from thehand-held power tool. In some embodiments, a single tab and actuator areincluded in the battery pack 1100.

As shown in FIG. 42 , the battery pack 1100 includes three battery cells1115 positioned within the casing 1105 and electrically coupled to theterminals 1125. The battery cells 1115 provide operational power (e.g.,DC power) to a hand-held power tool. In the illustrated embodiment, thebattery cells 1115 are arranged in series, and each battery cell 32 hasa nominal voltage of approximately 3.6V-4.0V, such that the battery pack1100 has a nominal voltage of approximately twelve-volts (12V). Thebattery cells 1115 have the same chemistry as the battery cellsdescribed above with respect to the battery pack 1000, and are, forexample, INR18650-15M lithium-ion rechargeable battery cellsmanufactured and sold by Samsung SDI Co., Ltd. of South Korea.

The power provided by the battery packs 1000 or 1100 to the motor 900 iscontrolled, monitored, and regulated using control electronics withinthe hand-held power tool and within the battery pack 1000, 1100, asillustrated in the electromechanical diagrams of FIGS. 44 and 45(described with respect to the battery pack 1000). For example, FIG. 44illustrates a controller 1200 associated with the battery pack 1000. Thecontroller 1200 is electrically and/or communicatively connected to avariety of modules or components of the battery pack 1000. For example,the illustrated controller 1200 is connected to a fuel gauge 1205, oneor more sensors 1210, a power tool interface 1215, a plurality ofbattery cells 1220, and a charge/discharge control module 1225 (optionalwithin battery pack). The controller 1200 includes combinations ofhardware and software that are operable to, among other things, controlthe operation of the battery pack 1000, activate the fuel gauge 1205(e.g., including one or more LEDs), monitor the operation of the batterypack 1000, etc. The one or more sensors 1210 include, among otherthings, one or more temperature sensors, one or more voltage sensors,one or more current sensors, etc. The controller 1200 also includes avariety of preset or calculated fault condition values related totemperatures, currents, voltages, etc., associated with the operation ofthe hand-held power tool.

In some embodiments, the controller 1200 includes a plurality ofelectrical and electronic components that provide power, operationalcontrol, and protection to the components and modules within thecontroller 1200 and/or battery pack 1000. For example, the controller1200 includes, among other things, a processing unit 1230 (e.g., amicroprocessor, a microcontroller, or another suitable programmabledevice), a memory 1235, input units 1240, and output units 1245. Theprocessing unit 1230 includes, among other things, a control unit 1250,an arithmetic logic unit (“ALU”) 1255, and a plurality of registers 1260(shown as a group of registers in FIG. 44 ), and is implemented using aknown computer architecture, such as a modified Harvard architecture, avon Neumann architecture, etc. The processing unit 1230, the memory1235, the input units 1240, and the output units 1245, as well as thevarious modules connected to the controller 1200 are connected by one ormore control and/or data buses (e.g., common bus 1265). The controland/or data buses are shown generally in FIG. 44 for illustrativepurposes. The use of one or more control and/or data buses for theinterconnection between and communication among the various modules andcomponents would be known to a person skilled in the art in view of theinvention described herein. In some embodiments, the controller 1200 isimplemented partially or entirely on a semiconductor (e.g., afield-programmable gate array [“FPGA”] semiconductor) chip, such as achip developed through a register transfer level (“RTL”) design process.

The memory 1235 includes, for example, a program storage area and a datastorage area. The program storage area and the data storage area caninclude combinations of different types of memory, such as read-onlymemory (“ROM”), random access memory (“RAM”) (e.g., dynamic RAM[“DRAM”], synchronous DRAM [“SDRAM”], etc.), electrically erasableprogrammable read-only memory (“EEPROM”), flash memory, a hard disk, anSD card, or other suitable magnetic, optical, physical, or electronicmemory devices. The processing unit 1230 is connected to the memory 1235and executes software instructions that are capable of being stored in aRAM of the memory 1235 (e.g., during execution), a ROM of the memory1235 (e.g., on a generally permanent basis), or another non-transitorycomputer readable medium such as another memory or a disc. Softwareincluded in the implementation of the battery pack 1000 can be stored inthe memory 1235 of the controller 1200. The software includes, forexample, firmware, one or more applications, program data, filters,rules, one or more program modules, and other executable instructions.The controller 1200 is configured to retrieve from memory and execute,among other things, instructions related to the control of the batterypack described herein. The controller 1200 can also store variousbattery pack parameters and characteristics (including battery packnominal voltage, chemistry, battery cell characteristics, maximumallowed discharge current, maximum allowed temperature, etc.). In otherconstructions, the controller 1200 includes additional, fewer, ordifferent components.

The power tool interface 1215 includes a combination of mechanical(e.g., the support portion 1015) and electrical components (e.g., theplurality of terminals 1025) configured to, and operable for,interfacing (e.g., mechanically, electrically, and communicativelyconnecting) the battery pack with a hand-held power tool (e.g., thehand-held power tool 100, 300, 500, and 700). For example, powerprovided from the battery pack 1000 to one of the hand-held power tools100, 300, 500, and 700, is provided through the charge/discharge controlmodule 1225 to the power tool interface 1215. The charge/dischargecontrol module 1225 includes, for example, one or more switches (e.g.,FETs) for controlling the charging current to and discharge current fromthe battery cells 1220. The power tool interface 1215 also includes, forexample, a communication line 1270 for providing a communication line orlink between the controller 1200 and a hand-held power tool.

The sensors 1210 include, for example, one or more current sensors, oneor more voltage sensors, one or more temperature sensors, etc. Forexample, the controller 1200 uses the sensors 1210 to monitor anindividual state of charge of each of the battery cells 1220, monitor acurrent being discharged from the battery cells 1220, monitor thetemperature of one or more of the battery cells 1220, etc., for faultcondition interrupts. If the voltage of one of the battery cells 1220 isequal to or above an upper voltage limit (e.g., a maximum chargingvoltage), the charge/discharge control module 1200 prevents the batterycells from being further charged or requests that a battery charger (notshown) provide a constant voltage charging scheme. Alternatively, if oneof the battery cells 1220 falls below a low-voltage limit, thecharge/discharge control module prevents the battery cells 1220 frombeing further discharged. Similarly, if an upper or lower operationaltemperature limit for the battery cells 1220 of the battery pack 1000 isreached, the controller 1200 can control the charge/discharge module1225 from being charged or discharged until the temperature of thebattery cells 1220 or the battery pack 1000 is within an acceptabletemperature range. Additional fault condition interrupts can beimplemented in the battery pack 1000 and are known to those skilled inthe art. The fuel gauge 1205 includes, for example, one or moreindicators, such as light-emitting diodes (“LEDs”). The fuel gauge 1205can be configured to display conditions of, or information associatedwith, the state-of-charge of the battery cells 1220.

In some embodiments, methods for protecting the lithium-based batterycells in the battery pack similar to those described in U.S. Pat. No.7,164,257, issued Jan. 16, 2007 and entitled “METHOD AND SYSTEM FORPROTECTION OF A LITHIUM-BASED MULTICELL BATTERY PACK INCLUDING A HEATSINK,” the entire content of which is hereby incorporated by reference,can be implemented to protect the battery pack 1000. However, unlike theprotection techniques described in U.S. Pat. No. 7,164,257, thehand-held power tools 100, 300, 500, and 700 and the battery pack 1000have higher current threshold limits (e.g., a maximum current thresholdof greater than approximately 60 amperes, a maximum current thresholdhaving a value between approximately 60 amperes and approximately 80amperes, etc.) as a result of, for example, the reduced impedance ofvarious components in the battery pack/hand-held power tool combination,the increased current capabilities of the motor 900, the thermaldissipation properties of the hand-held power tool, the balanced designof the hand-held power tool and battery pack, etc., as described herein.As such, the combination of the hand-held power tools 100, 300, 500, or700 and the battery pack 1000 is capable of transferring higherdischarge currents and more power from the battery pack 1000 to themotor 900 without the hand-held power tool 100, 300, 500, or 700entering a fault condition.

The power tool interface 1215 interfaces with a hand-held power tool,such as the hand-held power tools 100, 300, 500, and 700 illustrated inFIG. 45 . The hand-held power tool includes a controller 1300 associatedwith the power hand-held power tool 100, 300, 500, or 700. Thecontroller 1300 is electrically and/or communicatively connected to avariety of modules or components of the hand-held power tool. Forexample, the illustrated controller 1300 is connected to one or moreindicators 1305, a power input module 1310, a battery pack interface1315, one or more sensors 1320, a worklight 1325, a user input module1330, a trigger switch 1335 (connected to trigger 1340), and a FETswitching module 1345 (e.g., including the switching FETs describedabove). In some embodiments, the trigger switch 1335 is combined andintegral with the controller 1300 within a housing within the hand-heldpower tool. The controller 1300 includes combinations of hardware andsoftware that are operable to, among other things, control the operationof the hand-held power tool, activate the one or more indicators 1305(e.g., an LED), monitor the operation of the hand-held power tool, etc.The one or more sensors 1320 include, among other things, one or moretemperature sensors, one or more Hall Effect sensors, etc. By reducingthe impedance between the battery pack and the hand-held power tool asdescribed above, an inherent instability is introduced to the power toolsystem. As such, the controller 1300 calculates or includes, withinmemory, predetermined operational threshold values and limits foroperation. In some embodiments, the threshold values are dynamicallyadjusted based on operational characteristics of, for example, thebattery pack 1000, the motor 900, or control electronics (e.g., theswitching FETs). For example, if the temperature of the battery pack isincreasing rapidly or is nearing a maximum temperature limit, thebattery pack 1000 can communicate with the power tool and theoperational limits of the power tool or battery pack can be modified(e.g., increased or decreased). In some embodiments, when a potentialthermal failure (e.g., of a FET, the battery pack, or the motor) isdetected or predicted by the controller 1300, power to the motor 900 canbe limited interrupted until the potential for thermal failure isreduced. Additionally or alternatively, the power tool can communicatewith the battery pack 1000 to indicate when the hand-held power tool iscapable of receiving higher input currents.

In some embodiments, the controller 1300 includes a plurality ofelectrical and electronic components that provide power, operationalcontrol, and protection to the components and modules within thecontroller 1300 and/or hand-held power tool. For example, the controller1300 includes, among other things, a processing unit 1350 (e.g., amicroprocessor, a microcontroller, or another suitable programmabledevice), a memory 1355, input units 1360, and output units 1365. Theprocessing unit 1350 includes, among other things, a control unit 1370,an arithmetic logic unit (“ALU”) 1375, and a plurality of registers 1380(shown as a group of registers in FIG. 45 ), and is implemented using aknown computer architecture, such as a modified Harvard architecture, avon Neumann architecture, etc. The processing unit 1350, the memory1355, the input units 1360, and the output units 1365, as well as thevarious modules connected to the controller 1300 are connected by one ormore control and/or data buses (e.g., common bus 1385). The controland/or data buses are shown generally in FIG. 45 for illustrativepurposes. The use of one or more control and/or data buses for theinterconnection between and communication among the various modules andcomponents would be known to a person skilled in the art in view of theinvention described herein. In some embodiments, the controller 1300 isimplemented partially or entirely on a semiconductor (e.g., afield-programmable gate array [“FPGA”] semiconductor) chip, such as achip developed through a register transfer level (“RTL”) design process.

The memory 1355 includes, for example, a program storage area and a datastorage area. The program storage area and the data storage area caninclude combinations of different types of memory, such as read-onlymemory (“ROM”), random access memory (“RAM”) (e.g., dynamic RAM[“DRAM”], synchronous DRAM [“SDRAM”], etc.), electrically erasableprogrammable read-only memory (“EEPROM”), flash memory, a hard disk, anSD card, or other suitable magnetic, optical, physical, or electronicmemory devices. The processing unit 1350 is connected to the memory 1355and executes software instructions that are capable of being stored in aRAM of the memory 1355 (e.g., during execution), a ROM of the memory1355 (e.g., on a generally permanent basis), or another non-transitorycomputer readable medium such as another memory or a disc. Softwareincluded in the implementation of the hand-held power tool can be storedin the memory 1355 of the controller 1300. The software includes, forexample, firmware, one or more applications, program data, filters,rules, one or more program modules, and other executable instructions.The controller 1300 is configured to retrieve from memory and execute,among other things, instructions related to the control processes andmethods described herein. In other constructions, the controller 1300includes additional, fewer, or different components.

The battery pack interface 1315 includes a combination of mechanical(e.g., the battery pack receiving area 115, 315, 515, and 715) andelectrical components (e.g., the plurality of terminals 160, 350, 550,and 755) configured to and operable for interfacing (e.g., mechanically,electrically, and communicatively connecting) a hand-held power toolwith a battery pack (e.g., battery pack 1000). For example, powerprovided by the battery pack 1000 to one of the hand-held power tools100, 300, 500, and 700, is provided through the battery pack interface1315 to a power input module 1310. The power input module 1310 includescombinations of active and passive components to regulate or control thepower received from the battery pack 1000 prior to power being providedto the controller. The battery pack interface 1315 also supplies powerto the FET switching module 1345 to be switched by the switching FETs toselectively provide power to the motor 900. The battery pack interface1315 also includes, for example, a communication line 1390 for provideda communication line or link between the controller 1300 and the batterypack 1000.

The trigger switch 1335 is connected to the trigger 1340 (e.g., thetrigger 140, 335, 535, or 735) for controlling the power provided to themotor 900 through the switching FETs. In some embodiments, the amount oftrigger pull detected by the trigger switch is related to or correspondsto a desired speed of rotation of the motor 900. In other embodiments,the amount of trigger pull detected by the trigger switch 1335 isrelated to or corresponds to a desired torque. The worklight 1325 (e.g.,the worklight 150, 345, 545, and 750) is controlled by the controller1300. In some embodiments, the worklight 1325 is illuminated when thetrigger 1340 is pulled. In other embodiments, a dedicated switch orbutton is provided on the hand-held power tool or battery pack foractivating the worklight without pulling the trigger 1340. The worklight1325 can remain illuminated for a duration corresponding to an amount oftime that the trigger 1340 is pulled. Additionally or alternatively, theworklight is activated when the trigger 1340 is pulled and remainsilluminated for a predetermined period of time (e.g., 2 seconds, 10seconds, between 2 and 60 seconds, etc.) after the trigger 1340 ispulled, or the worklight 1325 is activated when the trigger 1340 ispulled and remains activated for a predetermined period of time (e.g., 2seconds, 10 seconds, between 2 and 60 seconds, etc.) after the trigger1340 has been released. The sensors 1320 include, for example, one ormore current sensors, one or more speed sensors, one or more Hall Effectsensors, one or more temperature sensors, etc. For example, the speed ofthe motor 900 can be determined using a plurality of Hall Effect sensorsto sense the rotational position of the rotor 910 (described below).

The user input module 1330 is operably coupled to the controller 1300to, for example, select a forward mode of operation or a reverse mode ofoperation, a torque and/or speed setting for the hand-held power tool(e.g., using the torque and/or speed switches), etc. In someembodiments, the user input module 1330 includes a combination ofdigital and analog input or output devices required to achieve a desiredlevel of operation for the hand-held power tool, such as one or moreknobs, one or more dials, one or more switches, one or more buttons,etc. The indicators 1305 include, for example, one or morelight-emitting diodes (“LED”). The indicators 1305 can be configured todisplay conditions of, or information associated with, the hand-heldpower tool. For example, the indicators 1305 are configured to indicatemeasured electrical characteristics of the hand-held power tool, thestatus of the hand-held power tool, etc.

The connections between a hand-held power tool and a battery pack, asdescribed above, are illustrated as schematics 1400 and 1405 in FIGS. 46and 47 , respectively. Specifically, the terminals 1410 and 1415 areconnected to the opposite ends of the cell or series of cells 1425. Asense terminal 1420 can be connected to one or more electricalcomponents, such as an identification component (i.e., a resistor) tocommunicate the identification of a characteristic of the battery pack1000, such as, for example, the nominal voltage of the battery pack1000, etc., or a temperature-sensing device or thermistor to communicatethe temperature of the battery pack 1000 and/or of the battery cell(s)1425.

In some embodiments, the electrical components may be other types ofelectrical components and may communicate other characteristics orinformation about the battery pack 1000 and/or of the battery cell(s)1000. It should also be understood that “communication” and“communicate”, as used with respect to the electrical components, mayalso encompass the electrical components having or being in a conditionor state which is sensed by a sensor or device capable of determiningthe condition or state of the electrical components.

The battery pack 1000 includes ten battery cells 1425 configured as fiveseries connections of two parallel cells. The illustrated embodiment ofthe hand-held power tool and battery pack combination includes fiveterminals: the battery positive (“B+”) terminal 1410, the batterynegative (“B−”) terminal 1415, the sense or communication terminal 1420,an identification terminal 1430, and a temperature terminal 1435. Inother embodiments, more or fewer terminals (e.g., B+, B−, and senseterminals) can be included in the connection between a hand-held powertool and a battery pack. In the circuits of FIGS. 46 and 47 , each ofthe battery pack 1000 and the hand-held power tool 100, 300, 500, or 700include a FET, 1440 and 1445 respectively, for controlling a dischargecurrent from the battery cells to the motor 900. In other embodiments,only one of the battery pack 1000 and the hand-held power tool 100, 300,500, or 700 includes a FET for controlling discharge current. Thecircuit 1405 illustrated in FIG. 47 is substantially similar to thecircuit illustrated in FIG. 46 with the exception of the number ofbattery cells included in the battery pack 1000, which includes fiveseries connected battery cells 1425.

The PCB's described above (e.g., the control PCB 165, the switching FETPCB 175, the surfboard PCB 355, 555, 760, the Hall Effect PCB 225, 410,610, and 815) with respect to the hand-held power tools 100, 300, 500,and 700 can be implemented in a variety of additional configurations.For example, as shown above with respect to the hammer drill 100 and thedrill/driver 300, the control PCB 165 and the FET switching PCB 175 ofthe hammer drill 100 can be combined into a single PCB, the surfboardPCB 355 of the drill/driver 300. In each configuration (i.e., the hammerdrill multi-PCB configuration or the drill/driver surfboard PCBconfiguration), the hand-held power tools include the Hall Effect PCBfor mounting sensors (e.g., Hall Effect sensors), as illustrated in FIG.48 . The Hall Effect PCB 1500 includes a circuit board 1505, a pluralityof Hall Effect sensors 1510, and a heat sink 1515 (e.g., an aluminum,aluminum-alloy, etc., heat sink). The Hall Effect PCB 1500 providessignals to the controller 1300 of the hand-held power tool related to,for example, rotation position, velocity, and/or acceleration. The HallEffect PCB, as illustrated in FIGS. 6, 11, 16, and 21 , is mounted on adistal end of the motor 900.

In a first alternative PCB configuration (e.g., to the multi-PCBconfiguration and the surfboard configuration), FIG. 49 illustrates aPCB configuration in which two parallel PCBs are mounted adjacent to themotor 900. The PCBs include a Hall Effect sensor and FET PCB 1520 and acontrol PCB 1525. The Hall Effect sensor and FET PCB 1520 includes atleast Hall sensors and FETs, and the control PCB 1525 includes at leasta motor control unit.

The Hall Effect sensor and FET PCB 1520 has a generally circular shapewith a through hole in the center. The motor shaft and motor bearingpass through the through hole. The Hall Effect sensor and FET PCB 1520has two generally flat mounting surfaces: a first face and a secondface. Similarly, the control PCB 1525 has two generally flat mountingsurfaces: a first face and a second face. The control PCB 1525 and HallEffect sensor and FET PCB 1520 are located coaxially about the rotor 910and their faces are generally parallel to each other. The PCBs 1520 and1525 are secured to an end of the motor 900. By locating FETs with HallEffect sensors 1510 on the single Hall Effect sensor and FET PCB 1520secured to the end of the motor 900, the Hall Effect sensor and FET PCB1520 is able to receive a large amount of air flow (e.g., from the vents145, 340, 540, and 745 and from the motor fan 200, 375, 585, and 790)for cooling in addition to reducing the internal wiring of the powertool (e.g., lowering wire resistance of the hand-held power tool).

FIG. 50 illustrates an alternative configuration for the PCBs in whichthe control PCB 1525 is not located coaxially about the motor shaft 955with the Hall Effect sensor and FET PCB 1520. In such embodiments, thecontrol PCB 1525 is located in another location within the power toolhousing (e.g., in the handle of the hand-held power tool, in thelocation of the surfboard PCB, etc.) and is electrically connected tothe Hall Effect sensor and FET PCB 1520 using, for example, a ribboncable. Furthermore, in such embodiments, the general shape of thecontrol PCB 1525 may not be circular. FIG. 50 illustrates the motor 900of a hand-held power tool along with an aluminum heat sink 1530, a rearbracket 1535, a wire support feature, a connecting portion 1540, and afan 1545. Like the embodiment illustrated by FIG. 49 , the Hall Effectsensor and FET PCB 1520 is secured to the end of the motor 900 and islocated coaxially about the rotor 910. The heat sink 1530 is mounted tothe motor 900 using mounting screws, and the Hall Effect sensor and FETPCB 1520 is mounted to the heat sink 1530 using mounting screws.Furthermore, the Hall Effect sensor and FET PCB 1520 is secured to themotor 900 using solder joints. The Hall Effect sensor and FET PCB 1520also includes the connecting portion 1540 to allow the Hall Effectsensor and FET PCB 1520 to receive power and communicate with thecontrol PCB 1525. With this configuration, the motor 900, the HallEffect sensor and FET PCB 1520, and the heat sink 1530, a large amountof air is pulled by the fan 1545 from the outside of the motor (e.g.,through vents) and around the heat sink 1530 to cool the Hall Effectsensor and FET PCB 1520.

Assembling a cordless, hand-held power tool in a balanced manner, asdescribed above (e.g., with respect to the hammer drill 100, thedrill/driver 300, the impact wrench 500, and the impact driver 700),produces a hand-held power tool with both increased short-durationoperational power (i.e., without causing the battery pack 1000 or thehand-held power tool to shut down or become non-operational) andincreased long-duration operational power (i.e., throughout a dischargecycle of the battery pack 1000) without causing the battery pack 1000 orthe hand-held power tool to shut down or become non-operational, asdescribed in detail below.

The performance of a hand-held power tool or an electrical combinationof a hand-held power tool and a battery pack can be measured andevaluated in a variety of ways. For example, the performance of ahand-held power tool can be evaluated using average Watts out of thehand-held power tool (there is a small efficiency loss associated withthe operation of the drive mechanism within the hand-held power toolwhich causes the average output power of the hand-held power tool to beslightly less than the average output power of the motor), average Wattsin (i.e., from the battery pack 1000), average voltage (e.g., of thebattery pack 1000), average current (e.g., from the battery pack 1000),average motor speed, average efficiency (i.e., average Watts outcompared to average Watts in), average torque generated by the hand-heldpower tool, full tool weight with or without battery, hand-held powertool electronics weight, motor weight (e.g., total motor weight, rotorweight, etc.), battery pack weight, motor stator stack length, motorstator outer diameter, motor stator inner diameter, motor rotordiameter, motor rotor length, motor bearing-to-bearing length, motorshaft length, motor shaft diameter, motor magnet length, etc.Additionally, ratios of any one of these characteristics to any other ofthese characteristics can be made and are illustrative of theperformance capabilities of the hand-held power tool. Exemplaryperformance ratios are provided below, and procedures for measuringand/or evaluating some of the noted characteristics are also providedbelow for the purpose of clarity.

Most of the characteristics of the hand-held power tool and/or batterypack provided above can be measured or obtained using methods wellwithin the capabilities of a person skilled in the art (e.g., weights,lengths, voltages, currents, speeds, torques, etc.). However, some ofthe above characteristics are gathered or obtained using, or during,precise testing procedures. For example, in order to obtain a maximumsustained output power and, for example, the associated currents andtorques, etc., a reproducible and repeatable procedure is implemented toensure accurate and reliable data. A series of exemplary testingprocedures are described in detail below with respect to the testing ofthe hand-held power tool and/or battery pack to provide appropriatecontext to some of the above-noted characteristics.

For example, one conventional technique for determining the maximumpower delivery of a hand-held power tool and/or the maximum efficiencythe hand-held power tool (or motor) employs a dynamometer. Thedynamometer is used to test the hand-held power tool using a braketorque load (e.g., a hysteresis brake). A procedure for measuring themotor power includes attaching the hand-held power tool including drivemechanism (or, alternatively, the hand-held power tool's motor alone) tothe dynamometer, providing an input power to the hand-held power toolusing the hand-held power tool's battery pack or a power supply, andoperating the hand-held power tool under varying load conditions (i.e.,levels of loading). During the test, the brake torque load is adjusted(e.g., corresponding to 25 Watt increments in output power, a rampedspeed, a ramped torque, etc.) and the voltage to the tool is fixed(e.g., according to the battery pack voltage). Typically, the brake isinitially set to a zero torque value. During the dynamometer test, aramp rate can be determined for the test. For example, the ramp ratethat is used during the test can be calculated as follows:

${{Ramp}{Rate}} = \frac{\left( {{Maximum}{Speed}} \right) - \left( {{Minimum}{Speed}} \right)}{{Time}{Length}{of}{Test}}$where the maximum speed is the maximum speed of the motor, the minimumspeed is the minimum intended speed of the motor during the test, andthe time length of test is the length of time that the test should taketo be completed. In some embodiments, the time length of the test isbetween approximately 10 seconds and approximately 25 seconds (e.g.,20.5 seconds). Thus, the ramp rate used during dynamometer testing hasunits of speed (i.e., RPM) over seconds. The test is conducted, forexample, by ramping the speed down and then up (e.g., increasing torqueand then decreasing torque). In some embodiments, inertia correction canbe used during the dynamometer testing.

Additionally or alternatively, in some embodiments, the torque of thebrake is either stepped-up in fixed increments over a predeterminedperiod of time, or the torque is gradually ramped-up at a predeterminedrate with respect to time (e.g., an inch-pounds/second ramp). In otherembodiments, the torque is not increased until thermal stabilization ofthe power tool is reached. At that point, the torque is again increased.When a thermal failure occurs, the maximum output torque can beidentified (e.g., the increment before thermal failure). Measurements ofthe motor's speed and the current provided to the motor are madethroughout the test. The gathered data can then be plotted on a graphsuch that speed, current, output power (i.e., speed multiplied bytorque), and efficiency (i.e., output power divided by input power) areprovided on the Y-axis and torque is provided on the X-axis. The peakoutput power, torque, etc., can be determined using this procedure.

The power output of one motor can then be compared to the power outputof another motor in a relative manner by evaluating, for example, peakpower output, peak efficiency, the shape of a speed vs. torque curve,the shape of the current vs. torque curve, etc. Using such comparisons,relative differences in peak output power and efficiency over ashort-run or short duration (e.g., 20-25 seconds during the dynamometertesting) can be evaluated. Such comparisons are particularlyillustrative of the operation of the hand-held power tool duringreal-world operating conditions in which the hand-held power tool mayonly be operated for intermittent short intervals of time. The greaterthe power that a hand-held power tool is capable of producing, thelarger (i.e., higher power demand) the application the hand-held powertool can be used to complete, or, alternatively, the faster thehand-held power tool is able to perform smaller (i.e., lower powerdemand) applications.

The capability of the hand-held power tool to deliver maximum continuouspower is evaluated in a similar manner to that described above, but theload is set to the same load point for the duration of the testing.However, the test can be performed multiple times at different loads inorder to determine the maximum continuous output power or theapproximate maximum continuous output power during the operation of thehand-held power tool. In some embodiments, the fixed load point can beselected based on, for example, input current to the hand-held powertool. The current load point is set to a maximum current value that doesnot result in a thermal failure of the hand-held power tool or thebattery pack, and that does not result in the hand-held power tool orbattery pack shutting down prematurely (e.g., before the battery packreaches a low-voltage cutoff value (see, for example, Tables 2 and 7below). In other embodiments, a load point corresponding to a specificvalue in units of torque, input power, or output power. Because torqueis proportional to current in DC motors, both can be considered fixed toeach other via a constant value. Such a test should only be consideredvalid if the hand-held power tool or component of the hand-held powertool does not fail (e.g., thermal failure of the hand-held power tool)and result in shut down prior to the natural end of battery packdischarge (e.g., as the result of one of the plurality of battery cellsreaching low battery cell voltage cutoff). Such a test can be consideredvalid if the battery pack fails (e.g., thermal failure of the batterypack) but the hand-held power tool does not fail (e.g., because of asingle faulty battery cell, etc.).

Each of the short-run test data and long-run test data for a hand-heldpower tool including one of a variety of motors (e.g., genericallycategorized by motor stator outer diameter) are provided below. The testdata provided related to a hand-held power tool being powered by abattery pack is provided with respect to a battery pack having a 5S2P(five-series, 2-parallel) configuration for an 18V nominal batter packvoltage (i.e., for the motors having an outer stator diameter of 50 mmor 60 mm) or a battery pack having three series-connected battery cellsand producing a battery pack nominal voltage of 12V (i.e., for the motorhaving an outer stator diameter of 40 mm). Each of Tables 1-5 provideranges of values for each characteristic of the hand-held powertool/battery pack. Tables 6-10 provide exemplary single-run performancecharacteristics for the hand-held power tools and battery packsdescribed herein. The ranges of values represent measured values from aseries of tests to evaluate the performance and operationalcharacteristics of the hand-held power tools. For the characteristics ofthe hand-held power tool/battery pack where a range is given (e.g.,either a closed range or an open-ended range), the value of thecharacteristic can take on any value within the range or be limited to asmaller range within the provided range. For example, the stator outerdiameter is indicated as being between 20 mm and 80 mm. However, thestator outer diameter can have a value that is within a subset of thatrange, such as an outer stator diameter of between 40 mm and 60 mm.

The ranges provided below exemplary and intended to be inclusive of thefull-range of possible values, which can vary slightly from onehand-held power tool to another. For example, a hand-held power toolincluding the motor 900 may have an average sustained power output ofbetween approximately 150 W and 800 W. A maximum Watts out (i.e.,short-run) of greater than approximately 400 W may have an actual valueof between approximately 400 W and approximately 700 W. Similarly, andefficiency values are give with respect to a lower limit, such as 65%efficiency. The efficiency has an actual value of greater than or equalto approximately 65% but less than 100%. The lowest values of open-endedranges are based on test data and should not be considered limiting torange of higher values that can be achieved when implementing theinvention described herein. Throughout testing, the hand-held powertools including the motor 900 described herein achieved output powers(i.e., of the hand-held power tool) of between approximately 150 W andapproximately 1200 W, depending on characteristics of the motor beingtested and the power source (e.g., battery pack) voltage for thehand-held power tool. For example, when the hand-held power toolincluding the motor 900 is powered by a battery pack having a nominalvoltage of 18V, the maximum output powers of the hand-held power toolwere in the range of approximately 400 W to approximately 1200 W. Whenthe hand-held power tool including the motor 900 is powered by a batterypack having a nominal voltage of 12V, the maximum output powers of thehand-held power tool were in the range of approximately 250 W toapproximately 500 W. When the hand-held power tool including the motor900 is powered by a battery pack having a nominal voltage of 18V, theaverage sustained output powers of the hand-held power tool were in therange of approximately 300 W to approximately 800 W. When the hand-heldpower tool including the motor 900 is powered by a battery pack having anominal voltage of 12V, the average sustained output powers of thehand-held power tool were in the range of approximately 150 W toapproximately 400 W.

In some embodiments of the invention, the average sustained output powerfor a hand-held power tool being powered by a battery pack having anominal voltage of 12V is, for example, greater than or equal toapproximately 150 W, greater than or equal to approximately 200 W,greater than or equal to approximately 250 W, greater than or equal toapproximately 300 W, or greater than or equal to approximately 350 W.

In some embodiments of the invention, the average sustained output powerfor a hand-held power tool being powered by a battery pack having anominal voltage of 18V is, for example, greater than or equal toapproximately 300 W, greater than or equal to approximately 350 W,greater than or equal to approximately 400 W, greater than or equal toapproximately 450 W, greater than or equal to approximately 500 W,greater than or equal to approximately 550 W, greater than or equal toapproximately 600 W, greater than or equal to approximately 650 W,greater than or equal to approximately 700 W, greater than or equal toapproximately 750 W.

In some embodiments of the invention, the maximum short-run output powerfor a hand-held power tool being powered by a battery pack having anominal voltage of 12V is, for example, greater than or equal toapproximately 250 W, greater than or equal to approximately 300 W,greater than or equal to approximately 350 W, greater than or equal toapproximately 400 W, or greater than or equal to approximately 450 W.

In some embodiments of the invention, the maximum short-run output powerfor a hand-held power tool being powered by a battery pack having anominal voltage of 18V is, for example, greater than or equal toapproximately 400 W, greater than or equal to approximately 450 W, orgreater than or equal to approximately 500 W, greater than or equal toapproximately 550 W, greater than or equal to approximately 600 W,greater than or equal to approximately 650 W, greater than or equal toapproximately 700 W, greater than or equal to approximately 750 W,greater than or equal to approximately 800 W, greater than or equal toapproximately 850 W, greater than or equal to approximately 900 W, orgreater than or equal to approximately 950 W.

The values for the characteristics provided below are approximate valuesbased on test data for the disclosed hand-held power tools. As a resultof the approximation, the values provided below are not exact and eachvalue may have a variance within the range of approximately +/−1-10%.

TABLE 1 Hand-Held Power Tool and Battery Pack Characteristics UnitsWeight (Tool only) g  900-1200 1500-1700 2400-2800 2900-3100 Weight(Tool and battery - g 1300-1600 2200-2400 3000-3500 3500-3800 ToolTotal) Weight (Tool and Battery w/ g — 2450-2700 3250-3800 3750-4100Side Handle) Weight (Motor + Electronics) g 300-350 400-450 600-700750-850 Weight (Battery Pack) g 350-450 600-700 600-700 600-700 TotalMotor Weight g 245-265 325-360 540-580 680-720 Stator Weight g 135-145190-210 310-330 390-410 Rotor Weight g 110-120 135-150 230-250 290-310Stator Length (Active Motor mm 22-32 14-32 14-32 25-35 Length) StatorOuter Diameter mm 20-60 30-70 40-80 40-80 Stator Inner Diameter mm 10-5020-60 30-70 30-70 Rotor Diameter mm 17-27 20-30 17-30 30-35 Rotor Lengthmm 29-39 20-30 24-34 31-41 Rotor Bearing-to-Bearing mm 50-60 40-50 70-8080-90 Length Rotor Shaft Length mm 55-80 55-80 75-90  85-100 Rotor ShaftDiameter mm 3-5 4-6 7-9 7-9 Rotor Magnet Length mm 29-39 20-30 24-3431-41

The total motor weight includes the weight of the stator and the weightof the rotor. The weight of the rotor includes the bearings, the fan,the permanent magnets, any spacers connected to the rotor shaft, and apinion for driving a gear assembly.

TABLE 2 Long-Run Performance Characteristics (Battery Pack) Units StatorOuter Diameter mm 40 50 60 Nominal Battery Pack Voltage V 12 18 18Average Volts V 10 16 16 Average Sustained Current A 25-35 30-40 30-45Average Sustained Power W >150 >300 >300 Output Average Sustained PowerW >250 >450 >450 Input Average Speed (Tool Output) RPM 270-290 275-305275-305 Average Efficiency % >60 >65 >65 Torque (Tool Output)lb-in >45 >95 >95 Motor Speed/Tool Output RPM/ <60 <60 <60 Speed RPMLength of Run s <360 <360 <360 Ampere-Hours Discharged A/h 2.5-2.72.6-2.8 2.6-2.8 Watt Hours W/h >15 >30 >30

TABLE 3 Long-Run Performance Characteristic Ratios (Battery Pack) UnitsStator Outer Diameter mm 40 50 60 Average Sustained PowerW/s >0.45 >1.0 >1.0 Output/Length of Run Average Sustained PowerW/g >0.4 >0.75 >.75 Output/electronics and motor weight AverageSustained Power W/g >0.12 >0.2 >0.2 Output/tool-only weight AverageSustained Power W/mm >3.5 >6 >5 Output/Stator Outer DiameterTorque/Stator Length lb-in/mm >1.2 >3 >3 Stator Length/Rotor Lengthmm/mm 0.37-0.54 0.21-0.43 0.21-0.54

TABLE 4 Short-Run Performance Characteristics (Battery Pack) UnitsStator Outer Diameter mm 40 50 60 60 Max Watts Out W >250 >400 >600 >700Nominal Voltage V 12 18 18 18 Current at Max Watts Out A 55-65 55-6575-90 75-95 Speed (Tool Output) at Max RPM 160-190 220-230 >300 >300Watts Out Watts In at Max Watts Out W 500-550  950-1000 >950 >950Efficiency at Max Watts Out % >45 >55 >60 >65 PeakEfficiency >55 >65 >65 >65 Motor Speed/Tool Output RPM/ <60 <60 <60 <60Speed RPM Torque (Tool Output) at Max lb-in >120 >180 >80 >110 Watts Out

TABLE 5 Short-Run Performance Characteristic Ratios (Battery Pack) UnitsStator Outer Diameter mm 40 50 60 60 Max Watts Out/tool-only weightW/g >0.2 >0.3 >0.3 >0.2 Max Watts Out/total tool weightW/g >0.15 >0.2 >0.2 >0.18 Torque/Stator Length lb-in/mm >3 >5 >3 >3 MaxWatts Out/Stator Diameter W/mm >6 >8 >8 >8

In addition to the above ranges and values for the performancecharacteristics of the hand-held power tool/battery pack, provided beloware values for each performance characteristic with respect an exemplarysingle test of the performance of the hand-held power tool/battery packincluding a motor with a 40 mm stator outer diameter (powered by a 12Vbattery pack) and a motor with a 50 mm stator outer diameter (powered byan 18V battery pack). The values for the characteristics provided beloware approximate values based on test data. As a result of theapproximation, the values provided below are not exact and each valuemay have a variance within the range of approximately +/−5-10%.

TABLE 6 Hand-Held Power Tool and Battery Pack Characteristics UnitsWeight (Tool only) g 1080 1647 2590 2980 Weight (Tool and battery - g1479 2334 3278 3668 Tool Total) Weight (Tool and Battery w/ g — 26043548 3938 Side Handle) Weight (Motor + Electronics) g 322 426 650 790Weight (Battery Pack) g 400 688 688 688 Total Motor Weight g 254 336.5560 700 Stator Weight g 139.5 194.5 320 400 Rotor Weight g 114.5 142 240300 Stator Length (Active Motor mm 30 24 22 30 Length) Stator OuterDiameter mm 40 50 60 60 Stator Inner Diameter mm 23 27 34.5 34.5 RotorDiameter mm 22 26 33.5 33.5 Rotor Length mm 34 27.9 28.5 36.5 RotorBearing-to-Bearing mm 54.3 46 76 84 Length Rotor Shaft Length mm 71 6584 92 Rotor Shaft Diameter mm 4 5 8 8 Rotor Magnet Length mm 34 27.928.5 36.5

TABLE 7 Long-Run Performance Characteristics (Battery Pack) Units StatorOuter Diameter mm 40 50 Average Volts V 10 16 Average Sustained CurrentA 27 32 Average Sustained Power Output W 166 350 Average Sustained PowerInput W 271 505 Average Speed (Tool Output) RPM 281 300 AverageEfficiency % 61 69 Torque (Tool Output) lb-in 50 100 Motor Speed/ToolOutput Speed RPM/ 55 48.5 RPM Length of Run s 334 310 Ampere-HoursDischarged A/h 2.6 2.75 Watt Hours W/h 15 30

TABLE 8 Long-Run Performance Characteristic Ratios (Battery Pack) UnitsStator Outer Diameter mm 40 50 Average Sustained Power W/s 0.5 1.13Output/Length of Run Average Sustained Power W/g 0.52 0.82Output/electronics and motor weight Average Sustained Power W/g 0.150.21 Output/tool-only weight Average Sustained Power W/mm 4.15 7Output/Stator Outer Diameter Torque/Stator Length lb-in/mm 1.67 4.2Stator Length/Rotor Length mm/mm 0.42 0.37

TABLE 9 Short-Run Performance Characteristics (Battery Pack) UnitsStator Outer Diameter mm 40 50 60 60 Max Watts Out W 259 550 735 835Nominal Battery Pack Voltage V 12 18 18 18 Current at Max Watts Out A 5961 84 95 Speed at Max Watts Out RPM 180 225 767 767 Watts In at MaxWatts Out W 525 970 1187 1215 Efficiency at Max Watts Out % 49 56 64 72Peak Efficiency % 62 70 72 78 Motor Speed/Tool Output Speed RPM/ 55 48.512 12 RPM Torque (Tool Output) at Max lb-in 122 207 82.5 117 Watts Out

TABLE 10 Short-Run Performance Characteristic Ratios (Battery Pack)Units Stator Outer Diameter mm 40 50 60 60 Max Watts Out/tool-onlyweight W/g 0.24 0.33 0.29 0.29 Max Watts Out/total tool weight W/g 0.180.24 0.23 0.24 Torque/Stator Length lb-in/mm 4.1 8.6 3.75 2.75 Max WattsOut/Stator Diameter W/mm 6.5 11 12.7 14.6

Thus, the invention provides, among other things, a cordless, hand-heldpower tool that includes a brushless direct current motor. The hand-heldpower tool is operable to and capable of producing increased short-run(i.e., short-duration) output power and increased long-run (i.e., longduration) output power as compared to prior cordless, hand-held powertools. Although the invention was primarily described above with respectto a hammer drill/driver, a drill/driver, an impact driver, and animpact wrench, the power tool can also be, for example, a saw, an anglegrinder, a bandsaw, a belt sander, a chainsaw, a circular saw, aconcrete saw, a disc sander, a floor sander, a jigsaw, a miter saw, arotary hammer, a grinder, a nail gun, a reciprocating saw, a scroll saw,a router, etc. Various features and advantages of the invention are setforth in the following claims.

What is claimed is:
 1. A power tool comprising: a battery pack interfaceconfigured to receive a battery pack that is removably coupled to ahousing of the power tool, the battery pack having a nominal voltage of18 Volts to 36 Volts; a brushless direct-current (“BLDC”) motor, theBLDC motor having an outer diameter of 50 millimeters to 80 millimetersand a weight of 336.5 grams to 720 grams; a switching array including aplurality of switching field effect transistors (“FETs”) electricallyconnected between the BLDC motor and the battery pack interface, theplurality of switching FETs configured for controlling application ofpower to the BLDC motor, wherein the plurality of switching FETs have adrain-to-source resistance of below 3 milli-Ohms; a controllerconfigured to generate a control signal to selectively enable anddisable the plurality of switching FETs in the switching array to drivethe BLDC motor with power provided from the battery pack; and an outputshaft coupled to the BLDC motor to provide an output of the power tool,wherein when powered by the battery pack the power tool is configured toproduce a maximum short-duration power output of at least 600 Watts andan average long-duration power output, throughout a discharge cycle ofthe battery pack, of at least 400 Watts, and a ratio of Ampere-hours(Ah) discharged by the battery pack for providing the averagelong-duration power output to length of run in seconds (s) of theaverage long-duration power output is at least 0.0072Ah:1 s.
 2. Thepower tool of claim 1, wherein a stator length of the BLDC motor isbetween 22 millimeters and 35 millimeters.
 3. The power tool of claim 1,wherein a stator weight of the BLDC motor is between 195 grams and 400grams.
 4. The power tool of claim 1, wherein the maximum short-durationpower output refers to a power output during a duration of between 20seconds and 25 seconds.
 5. The power tool of claim 1, wherein a ratio ofthe maximum short-duration power output to the outer diameter of theBLDC motor is at least 10 Watts:1 millimeter.
 6. The power tool of claim1, wherein a ratio of the average long-duration power output of thepower tool to the outer diameter of the BLDC motor is at least 5 Watts:1millimeter.
 7. The power tool of claim 1, wherein an energy consumed bythe power tool for providing the average long duration power output isat least 30 Watt Hours.
 8. The power tool of claim 1, wherein a rotorweight of the BLDC motor is between 142 grams and 300 grams.
 9. Thepower tool of claim 1, wherein a rotor length of the BLDC motor isbetween 24 millimeters and 34 millimeters.
 10. A power tool comprising:a battery pack interface configured to receive a battery pack that isremovably coupled to a housing of the power tool, the battery packhaving a nominal voltage of 18 Volts to 36 Volts; a brushlessdirect-current (“BLDC”) motor, the BLDC motor having an outer diameterof 50 millimeters to 80 millimeters and a weight of 336.5 grams to 720grams; a switching array including a plurality of switching field effecttransistors (“FETs”) electrically connected between the BLDC motor andthe battery pack interface, the plurality of switching FETs configuredfor controlling application of power to the BLDC motor, wherein theplurality of switching FETs have a drain-to-source resistance of below 3milli-Ohms; a controller configured to generate a control signal toselectively enable and disable the plurality of switching FETs in theswitching array to drive the BLDC motor with power provided from thebattery pack; and an output shaft coupled to the BLDC motor to providean output of the power tool, wherein when powered by the battery packthe power tool is configured to produce a maximum short-duration poweroutput of at least 600 Watts and an average long-duration power output,throughout a discharge cycle of the battery pack, of at least 400 Watts,and an energy consumed by the power tool for providing the average longduration power output is at least 30 Watt Hours.
 11. The power tool ofclaim 10, wherein a stator length of the BLDC motor is between 22millimeters and 35 millimeters.
 12. The power tool of claim 10, whereina stator weight of the BLDC motor is between 195 grams and 400 grams.13. The power tool of claim 10, wherein the maximum short-duration poweroutput refers to a power output during a duration of at least between 20seconds and 25 seconds.
 14. The power tool of claim 10, wherein a ratioof the maximum short-duration power output to the outer diameter of theBLDC motor is at least 10 Watts:1.
 15. The power tool of claim 10,wherein a ratio of the average long-duration power output of the powertool to the outer diameter of the BLDC motor is at least 5 Watts:1. 16.The power tool of claim 10, wherein a rotor weight of the BLDC motor isbetween 142 grams and 300 grams.
 17. The power tool of claim 10, whereina rotor length of the BLDC motor is between 24 millimeters and 34millimeters.
 18. A power tool comprising: a battery pack interfaceconfigured to receive a battery pack that is removably coupled to ahousing of the power tool, the battery pack having a nominal voltage of18 Volts to 36 Volts; a brushless direct-current (“BLDC”) motor, theBLDC motor having an outer diameter of 50 millimeters to 80 millimetersand a weight of 336.5 grams to 720 grams; a switching array including aplurality of switching field effect transistors (“FETs”) electricallyconnected between the BLDC motor and the battery pack interface, theplurality of switching FETs configured for controlling application ofpower to the BLDC motor, wherein the plurality of switching FETs have adrain-to-source resistance of below 3 milli-Ohms; a controllerconfigured to generate a control signal to selectively enable anddisable the plurality of switching FETs in the switching array to drivethe BLDC motor with power provided from the battery pack; and an outputshaft coupled to the BLDC motor to provide an output of the hand heldpower tool, wherein when powered by the battery pack the power tool isconfigured to produce a maximum short-duration power output of at least600 Watts and an average long-duration power output, throughout adischarge cycle of the battery pack, of at least 400 Watts, wherein arotor weight of the BLDC motor is between 142 grams and 300 grams. 19.The power tool of claim 18, wherein the maximum short-duration poweroutput refers to a power output during a duration of between 20 secondsand 25 seconds.
 20. The power tool of claim 18, wherein a ratio of themaximum short-duration power output to the outer diameter of the BLDCmotor is at least 10 Watts:1.
 21. The power tool of claim 18, wherein aratio of the average long-duration power output of the power tool to theouter diameter of the BLDC motor is at least 5 Watts:1.
 22. The powertool of claim 18, wherein an energy consumed by the power tool forproviding the average long duration power output is at least 30 WattHours.
 23. The power tool of claim 18, wherein a stator length of theBLDC motor is between 22 millimeters and 35 millimeters.
 24. The powertool of claim 18, wherein a stator weight of the BLDC motor is between195 grams and 400 grams.
 25. A power tool comprising: a battery packinterface configured to receive a battery pack that is removably coupledto a housing of the power tool, the battery pack having a nominalvoltage of 18 Volts to 36 Volts; a brushless direct-current (“BLDC”)motor, the BLDC motor having an outer diameter of 50 millimeters to 80millimeters and a weight of 336.5 grams to 720 grams; a switching arrayincluding a plurality of switching field effect transistors (“FETs”)electrically connected between the BLDC motor and the battery packinterface, the plurality of switching FETs configured for controllingapplication of power to the BLDC motor, wherein the plurality ofswitching FETs have a drain-to-source resistance of below 3 milli-Ohms;a controller configured to generate a control signal to selectivelyenable and disable the plurality of switching FETs in the switchingarray to drive the BLDC motor with power provided from the battery pack;and an output shaft coupled to the BLDC motor to provide an output ofthe hand held power tool, wherein when powered by the battery pack thepower tool is configured to produce a maximum short-duration poweroutput of at least 600 Watts and an average long-duration power output,throughout a discharge cycle of the battery pack, of at least 400 Watts,wherein a rotor diameter of the BLDC motor is between 17 millimeters and30 millimeters.
 26. The power tool of claim 25, wherein a ratio ofAmpere-hours (Ah) discharged by the battery pack for providing theaverage long-duration power output to length of run in seconds (s) ofthe average long-duration power output is at least 0.0072Ah:1 s.
 27. Thepower tool of claim 25, wherein a stator weight of the BLDC motor isbetween 195 grams and 400 grams.
 28. The power tool of claim 25, whereina stator length of the BLDC motor is between 22 millimeters and 35millimeters.
 29. The power tool of claim 25, wherein a rotor weight ofthe BLDC motor is between 142 grams and 300 grams.
 30. The power tool ofclaim 25, wherein the rotor length of the BLDC motor is between 24millimeters and 34 millimeters.